12th Physics Objectives + short questions

UNIT 12

ELECTROSTATICS

MULTIPLE CHOICE QUESTIONS

1. The existence of human body is attached with 12112054

a) Electric force b) Gravitational force

c) Nuclear force d) None

2. All those substances which do not have free electrons are called 12112055

a) Conductor b) Semiconductors

c) Insulators d) None

3. If air is replaced by any other dielectric medium the force of attraction or repulsion between two charges 12112056

a) Decreases b) Increases

c) Vanishes d) Remains same

4. In SI system, the value of permittivity of free space is 12112057

a) 6.85 ´ 10^–12 C² N^–1 m^–2

b) 7.85 ´ 10^–12 C² N^–1 m^–2

c) 8.85 ´ 10^–12 C² N^–1 m^–2

d) None

5. The relative permittivity of free space has the value equal to 12112058

a) 1.0 b) 1.006

c) 78.5 d) 2.1

6. Value of K depends upon 12112059

a) System of unit b) Nature of medium

c) Both a & b d) None

7. Value of proportionality constant K in vacuum is 12112060

a) 8 ´ 10⁹ Nm²C^–2 b) 9 ´ 10⁹ Nm²C^–2

c) 10 ´ 10⁹ Nm²C^–2 d) 9 ´ 10¹⁰ Nm²C^–2

8. Value of dielectric constant Î_r for water is

a) 25 b) 2.1 12112061

c) 3.40 d) 78.5

9. Concept of field lines of force was introduced by 12112062

a) Coulomb b) Faraday

c) Franklin d) Gauss

10. Unit of electric intensity is 12112063

a) NC^–1 b) Vm^–1

c) Both a & b d) None

11. If we move away from a charge, the magnitude of electric intensity will

12112064

a) Remain constant b) Increase

c) Decrease d) Zero

12. When area is neither perpendicular nor parallel to the field lines, then electric flux is 12112065

a) EA Cos q b) EA Sin q

c) E.A d) Both a & c

13. The magnitude of electric intensity due to point charge is 12112066

a) b)

c) d) None

14. For a positive charge electric field lines are directed (Board 2013) 12112067

a) Towards charge

b) Away from charge

c) Both a & b

d) None

15. The potential difference between two points in an electric field is 12112068

a) b)

c) d)

16. Electric potential energy difference and electric potential difference between two points is 12112069

a) DV = q_oDU b) DU= q_o DV

c) DV q_o E d) DU = q_o w

17. Electric lines of force are 12112070

a) Real b) Imaginary

c) Complex d) None of these

18. Selenium is 12112071

a) Conductor b) Insulator

c) Photo conductor d) Semi-conductor

19. Electric flux is a 12112072

a) Scalar quantity b) Vector quantity

c) Both a & b d) None

20. Unit of electric flux is 12112073

a) NC^–1 b) N m^–2 C^–1

c) C² N^–1 m^–1 d) N m² C^–1

21. Electric flux through a surface enclosing a charge is 12112074

a) q/_ob) _o/q_o

c) _o q d) None

22. Flux passing through a closed surface does not depend upon 12112075

a) Shape b) Medium

c) Charge d) All

23. The electric field present inside a hollow charged sphere is 12112076

a) Maximum b) Same

c) Zero d) Infinite

24. Gaussian surface is 12112077

a) Imaginary b) Closed

c) Both a & b d) Real

25. One volt is equal to 12112078

a) 1 newton/coulomb b) 1 farad/coulomb

c) 1 joule/1 coulomb d) None

26. Positive charges always tend to move from 12112079

a) Lower to higher potential

b) Higher to lower potential

c) Does not move

d) All

27. The dielectric constant of rubber is

a) 2 b) 2.94 12112080

c) 3.40 d) 2.1

28. Millikan devised a technique to measure the charge of an electron in 12112081

a) 1889 b) 1809

c) 1929 d) 1909

29. The expression for the radius of the droplet falling under the action of gravity is 12112082

a) b)

c) d) None

30. 1.6 x 10^–19 J is always equal to 12112083

a) 1 farad b) 1 coulomb

c) newton/ coulomb d) Electron-volt

31. Electron-volt is a unit of 12112084

a) Capacitance b) Energy

c) Potential d) Electric intensity

32. Range of electric force is 12112085

a) Small b) Large

c) Medium d) None

33. Charge on an electron is 12112086

a) 9.1 x 10^–31 C b) 1.6 ´ 10^–19 C

c) 2.1 x 10^–19 C d) 1.27 x 10^-19C

34. Capacitance of a capacitor depends upon

a) Geometry of capacitor 12112087

b) Medium between plates

c) Separation between plates

d) All

35. If medium between the plates of a parallel plate capacitor is air or vacuum, then its capacitance is 12112088

a) b)

c) d)

36. Expression for energy stored in a capacitor is 12112089

a) b)

c) d) None

37. Photocopier and inkjet printer are the application of 12112090

a) Electron b) Electricity

c) Magnetism d) Electrostatics

38. In the presence of a dielectric the capacitance of a capacitor 12112091

a) Increases b) Decreases

c) Same d) None

39. The direction of vector area is 12112092

a) Parallel to area

b) Perpendicular to area

c) Both a & b

d) None

40. The SI unit of capacitance is 12112093

a) farad b) gauss

c) volt d) coulomb

41. If a charge is moved against the electric field, it will gain 12112094

a) Potential energy

b) Kinetic energy

c) Mechanical energy

d) Electric potential energy

42. When two capacitors of capacitance C each are connected in series, their equivalent capacitance is 12112095

a) b) C

c) 2C d)

43. Electric force as compared to gravitational force is 12112096

a) Very weak b) Very strong

c) Zero d) Infinite

44. A system of two equal and opposite point charges separated by a small distance is called 12112097

a) Generator b) Capacitor

c) Condenser d) Dipole

45. The negative of potential gradient is

a) Potential energy 12112098

b) Electric field intensity

c) Electromotive force

d) Electrostatic force

46. The electrostatic energy of a parallel plate capacitor is given by 12112099

a) b)

c) d) None

47. When a dielectric material is placed in an electric field it 12112100

a) Conducts b) Magnetizes

c) Polarizes d) Undergoes electrolysis

48. In the direction indicated by an electric field line of positive charge 12112101

a) Electric intensity decreases

b) Electric potential decreases

c) Both a & b

d) None

49. The negative sign in the expression of potential gradient of E = - D V / D r shows that the direction of E is along the:

a) Increasing potential 12112102

b) Decreasing potential

c) Increasing strength

d) Negative potential

50. If 4 ´ 10²⁰ eV of energy is required to move a charged of 1C between two points then the potential difference between the points is: 12112103

a) 4 ´ 10²⁰ V b) 64 ´ 10¹⁹V

c) 64 ´ 10¹⁸V d) 64V

51. A positive charge is placed at the center of sphere of radius r, then the electric flux depends upon: 12112104

a) The radius of the sphere

b) Quantity of charge

c) The intensity of the electric field

d) All of the above

52. Neutral zone in electric field of two similar charges is region where: 12112105

a) Both positive and negative charges are present

b) Equal quantity of both positive and negative charges are present

c) An electric dipole exists

d) No electric field line passes

53. Two metallic spheres of radius 1 cm and 2 cm get equal quantity of charge. Which has greater surface charge density?12112106

a) 1^st sphere

b) 2^nd sphere

c) Both get equal surface

d) None of these

54. The capacity of a condenser is 4 ´ 10^-6 farad and its potential is 100 volt. The energy released on discharging it fully will be: 12112107

a) 0.02 joule b) 0.04 joule

c) 0.025 joule d) 0.05 joule

55. is measured in: 12112108

a) Hm^-1 b) Wm^-1

c) Nm^-1 d) Fm^-1

56. A 6mF capacitor is charged from 10 volt to 20 volt. Increase in energy will be:

12112109

a) 18 ´ 10^-4 joule b) 3 ´ 10^-4 joule

c) 4.5 ´ 10^-4 joule d) 9 ´ 10^-4 joule

57. Two capacitors of capacities C₁ and C₂ are connected in parallel. If a charge Q is given to the combination the charge gets shared. The ratio of the charge on the capacitor C₁ to the charge on the capacitor C₂ is: 12112110

a) C₁C₂ b)

c) d) C1 + C2

58. Two plates are 1cm apart and the potential difference between them is 10 volt. The electric field between the plates is: 12112111

a) 10NC^-1 b) 500NC^-1

c) 1000NC^-1 d) 250NC^-1

59. A sheet of aluminum foil of negligible thickness is introduced between the plates of a capacitor 12112112

a) Increases

b) Decreases

c) Remains uncharged

d) Becomes infinite

60. What is the force of attraction on a proton placed between the two parallel plates containing equal positive charges? 12112113

a) 2.6 ´ 10^-19N b) 9 ´ 10^-19N

c) 5 ´ 10^-19N d) Zero

61. A cloud whose base is 500m above the ground. The potential difference between the base of the cloud and the ground is 200MV. A rain drop with a charge of 4.0´10^-12C is in the region between the cloud and the ground. What is electrical force on the rain drop? 12112114

a) 1.6´10^-6 N b) 8´10^-4 N

c) 1.6´10^-3 N d) 0.40 N

62. On moving a charge of 20 coulomb by 2cm, 2J of work in done, then the potential difference between the points is:

12112115`

a) 0.1 V b) 8 V

c) 2 V d) 0.5 V

63. A positively charged glass rod attracts a suspended particle. The particle is: 12112116

a) Uncharged and insulated

b) Negatively charged

c) Positively charged

d) Earthen

64. A uniform electric field is represented by a set of lines which are: 12112117

a) parallel and equally spaced b) converging

c) diverging d) circular

65. If the distance between two charges is doubled and the charges are doubled then the coulomb’s force becomes: 12112118

a) half b) four times

c) remaining same d) eight times

66. To eliminate stray electric field interference, circuits of sensitive electronic devices are enclosed in: 12112119

a) insulating box b) metal box

c) wooden box d) none of these

67. If the vector area is parallel to the field lines, then electric flux is: 12112120

a) a maximum

b) infinite

c) minimum

d) remained the same

68. When the oppositely charged metal plates are placed parallel to each other then the charged reside on their: 12112121

a) outer surface

b) inner surface

c) they become neutral

d) inner and outer surface

69. The first discovered subatomic particle is:

12112122

a) proton b) electron

c) neutron d) meson

70. The value of relative permittivity Î_r, for various dielectric is always: 12112123

a) less than unity

b) equal to unity

c) larger than unity

d) slightly less than unity

71. The electric force of repulsion between two electrons at a distance of 1m is:

12112124

a) 1.8 N b) 1.5 ´ 19^-9N

c) 2.30 ´ 10^-28N d) 2.30 ´ 10^-27N

72. An electric field can deflect: 12112125

a) neutrons b) x-rays

c) g-rays d) charged particles

73. The presence of a fish by other fish can be detected by 12112126

a) Gravitational field

b) Electric field

c) Magnetic field

d) None of these

74. A test charge means a charge of: 12112127

a) – 1C b) + 1C

c) 1 electron d) + 5C

SHORT ANSWERS

Q.1 Give the properties of electric charge. 12112128

Ans.

Q.2. What is electric force? 12112129

Q.3 State Coulomb’s law. 12112130

1. Q.4 Find the nature of K in Coulomb’s law. 12112131

Q.5 What is the effect of medium on Coulomb’s force? 12112132

Q.6 Why electric force and gravitational forces are considered to be the basic forces? 12112133

Q.7. Calculate the electric intensity due to point charge. 12112134

Q.8 What is photo conductor? 12112135

Q.9 The interior of a hollow charged metal sphere is a field free region. Where this fact is applied? 12112136

Q.10 What is a Gaussian surface? 12112137

Q.11 How flux is calculated through a Gaussian surface? 12112138

Q.12 What is the difference between potential difference and electric potential or voltage? 12112139

Q.13 What do you mean by potential gradient? 12112140

Q.14 Prove = 12112141

Q.15 What is an electron – volt?

(Board 2015) 12112142

Q.16 What is the principle to calculate the charge on electron by Millikan’s method? 12112143

Q.17 What are the factors upon which the capacitance of capacitor depends?

12112144

Q.18 How the capacitance of a parallel plate capacitor can be increased? 12112145

Q.19 What is the effect of the polarization due to dielectric? 12112146

UNIT 13

CURRENT ELECTRICITY

MULTIPLE CHOICE QUESTIONS

1. Current electricity is the branch of Physics which deals with electric charges 12113040

a) At rest b) In motion

c) Both a & b d) None

2. The electric current may be caused due to

12113041

a) Electrons b) Negative ions

c) Positive ions d) All

3. In metallic conductors, current is due to

12113042

a) Electrons b) Protons

c) Ions d) All

4. In gases current may be due to 12113043

a) Electrons b) Protons

c) Ions d) Electrons and Ions

5. Conventional current flows from

12113044

a) Negative terminal to positive terminal

b) Positive terminal to negative terminal

c) Both a & b d) None

6. The effects of electric current are 12113045

a) Magnetic effect b) chemical effect

c) Heating effect d) All

7. The drift velocity is of the order of

12113046

a) 10^–2 ms^–1 b) 10^–3 ms^–1

c) 10^–4 ms^–1 d) 10^–5 ms^–1

8. The source(s) of current is (are): 12113047

a) Cells b) Electric generator

c) Thermocouple d) All

9. An apparatus containing electrodes and electrolytes is called: 12113048

a) Galvanometer

b) Ammeter

c) Voltameter

d) None

10. The working principle of electroplating is

a) Electrolysis 12113049

b) Potentiometer

c) Wheatstone bridge

d) None

11. The SI unit of resistivity is 12113050

a) W– m b) W m²

c) W m³ d) W

12. The SI unit of conductance is 12113051

a) Ohm b) Ohm-meter

c) Mho d) Mho-meter

13. If the resistivity of a material is large, then it is 12113052

a) Conductor b) Poor conductor

c) good conductor d) Insulator

14. When resistances are arranged in series their equivalent resistance 12113053

a) Increases b) Decreases

c) Remain same d) None

15. The liquid that is used to conduct current is called 12113054

a) Electrolysis b) Electrode

c) Electrolyte d) Cathode

16. Specific resistance of a conductor depends upon its 12113055

a) Length b) Area

c) Material d) All

17. The SI unit of conductivity is 12113056

a) (ohm–m)^–1 b) mho m^–1

c) Both a & b d) None

18. Colour code of yellow colour is 12113057

a) 3 b) 4

c) 5 d) 6

19. The fourth band on a carbon resistor gives

a) Tolerance b) First digit 12113058

c) 2^nd digit d) All

20. If the fourth band is absent, then tolerance is understood to be 12113059

a) ±5% b) ±10%

c) ±20% d) ±25%

21. A rheostat can be used as a 12113060

a) Variable resistance

b) Potential divider

c) Both a & b

d) None

22. SI unit of EMF is 12113061

a) Volt b) Joule/coulomb

c) Both a & b d) Farad

23. Which electrical quantity has the same units as electromotive force? 12113062

a) Charge b) Current

c) Potential difference d) Power

24. The electrode connected with negative terminal of the battery is called 12113063

a) Cathode b) Anode

c) Electrolyte d) All

25. The terminals which lead the current into or out of the electrolyte is (are) known

a) Anode b) Cathode 12113064

c) Electrodes d) Diodes

26. The study of conduction of electricity through liquids is known as 12113065

a) Conductivity b) Resistivity

c) Reactance d) Electrolysis

27. Kilowatt-hour is the unit of 12113066

a) Charge b) Energy

c) Power d) Voltage

28. Ohm’s law can be expressed as 12113067

a) I = VR b) R = IV

c) V = RI d) V =

29. Electric bulb does not obey Ohm’s law because 12113068

a) Temperature changes

b) Resistance changes

c) Heat is produced

d) All

30. Which can be used as unit of energy?

a) Nm^–1 b) VA 12113069

c) VC^–1 d) Watt sec

31. For non-ohmic devices, the graph between V and I is 12113070

a) Straight line b) Circle

c) Curve d) Elliptical

32. The reciprocal of resistance is known as

12113071

a) Reactance b) Conductance

c) Conductivity d) Resistivity

33. The sum of currents in various resistors meeting at a point of the circuit 12113072

a) Equals to the total current

b) Exceed the total current

c) Less than total current

d) None of above

34. The coil wound over an insulating cylinder i.e. rheostat is of which material?

a) Iron b) Copper 12113073

c) Aluminum d) Manganin

35. A heat sensitive resistor is called 12113074

a) Thermistor b) Variable resistor

c) Fixed resistor d) None

36. Whenever current is drawn from a cell, its terminal potential difference and emf become 12113075

a) Different b) Same

c) Zero d) Negative

37. Algebric sum of current meeting at a point is zero is a statement of 12113076

a) Kirchhoff’s 1^st law

b) Faraday’s law

c) Ampere’s law

d) None

38. If a resistor is traversed in the direction of current, the potential change is 12113077

a) Negative b) Positive

c) Zero d) Infinite

39. If the source of emf is traversed from negative to positive terminal, the potential change is: 12113078

a) Negative b) Positive

c) Zero d) Constant

40. The Kirchhoff’s first rule is the manifestation of law of conservation of

12113079

a) Mass b) Momentum

c) Energy d) Charge

41. The Kirchhoff’s 2^nd rule is the manifestation of law of conservation of

12113080

a) Mass b) Momentum

c) Energy d) Charge

42. Wheatstone bridge is used to measure the unknown 12113081

a) Current b) Voltage

c) Resistance d) None

43. A Wheatstone bridge consists of ----- resistors. 12113082

a) 3 b) 4

c) 5 d) 2

44. A potentiometer can be used as to:-

12113083

a) Determine emf of a cell

b) Compare emfs

c) Measure accurate value of Current

d) All of above

45. The proportionality constant between current and potential difference is 12113084

a) P b) R

c) d) V

46. The best instrument used for the accurate measurement of emf of a cell is 12113085

a) Voltmeter

b) Ammeter

c) Wheatstone bridge

d) Potentiometer

47. The electrical resistance of a metal 12113086

a) Increases with the increase of temperature

b) Decrease with increase of temperature

c) Independent of temperature

d) Conversion Mechanical energy into heat energy

48. A thermocouple converts 12113087

a) Electrical energy into solar energy

b) Heat energy into electrical energy

c) Mechanical energy into electrical energy

d) Mechanical energy into heat energy

49. The resistivity of a material in terms of its resistance R, Cross-sectional area ‘A’ and length ‘L’ is given by 12113088

a) b)

c) d)

50. Three resistors each of one ohm are connected to form triangle. The equivalent resistance is: 12113089

a) b)

c) d)

51. A wire when connected to 220V mains supply has power dissipation P₁. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is P₂, then P₂: P₁ is: 12113090

a) 1 b) 2

c) 3 d) 4

52. The resistance of a wire is , the wire is stretched to double of its original length then new resistance will be:

a) b) 12113091

c) d)

53. A 10 ampere fuse wire can withstand a maximum power of 2 watt in the circuit. The resistance of the fuse wire is: 12113092

a) 0.2 Ω b) 5 Ω

c) 0.02 Ω d) 200 Ω

54. Internal resistance and emf of a cell can be determined by an instrument: 12113093

a) CRO

b) AVO meter

c) Both CRO and AVO meter d) Potentiometer

55. Let an emf of 120V of negligible resistance connected across a resistance of 1000 ohms. Then the current flowing through the circuit is: 12113094

a) 120 A b)

c) d)

56. For an open circuit: 12113095

a) b)

c) d)

57. Maximum power is delivered to a load when internal resistance of source is

a) Less than load 12113096

b) Equal the load resistance

c) Greater than the load resistance d) Does not depend on load resistance

58. How many electrons per second constitute a current of one micro ampere?

a) One electron 12113097

b) 10^-6 electrons

c) 10⁶ electrons

d) 6.25 × 10¹² electrons

59. In Wheatstone bridge all the four arms have equal resistance R. If the resistance of galvanometer arm is also R, the equivalent resistance of the combination is 12113098

a) R/4 b) R/2

c) R d) 2R

60. Heat generated by a 40 watt bulb in one hour: 12113099

a) 4800 J b) 14400 J

c) 144000 J d) 4400 J

61. Which of the following has a positive temperature coefficient? 12113100

a) Carbon b) Silicon

b) Germanium d) Iron

62. The apparatus used to compare the emf of two cells is: 12113101

a) A wheat stone bridge

b) Galvanometer

c) Potentiometer

d) Ammeter

63. Which of the following metal has the lowest value of temperature coefficient of resistivity? 12113102

a) Silver b) Gold

c) Copper d) Aluminum

64. If a carbon resistance has red, violet and orange bands then its resistance is:

a) 270 ohms 12113103

b) 2700 ohms

c) 27000 ohms

d) 24300 to 29700 ohms

65. In a house circuit, all the electrical appliances are connected in parallel to each other between the line and neutral wires to get: 12113104

a) Same current

b) Same current and voltage

c) Different current but same potential difference

d) Different currents and potential differences

SHORT ANSWERS

Q.1 What is current electricity? 12113105

Q.2 Give some applications of current electricity. 12113106

Q.3 Define electric current and its units.

12113107

Q.4 What are the charge carriers which constitute current? 12113108

Q.5 What is conventional current? 12113109

Q.6 What is drift velocity? 12113110

Q.7 What is the total current in liquids and gases? 12113111

Q.8 What are the sources of current?

12113112

Q.9 What are the effects of current?

12113113

Q.10 What is a voltametor? 12113114

Q.11 What is electroplating? 12113115

Q.12 What are Ohmic devices? 12113116

Q.13 What are Non-Ohmic devices? Give example. 12113117

Q.14 What is resistivity or specific resistance? 12113118

Q.15 What is conductance and conduc-tivity? 12113119

Q.16 What is the effect of temperature on resistance? 12113120

Q.17 Define temperature coefficient of resistance. 12113121

Q.18 What is tolerance? 12113122

Q.19 What is electromotive force? 12113123

Q.20 What is the difference between electromotive force and terminal potential difference? 12113124

Q.21 What are the rules for finding the potential changes when we apply kirchhoff’s 2^nd rule? 12113125

Q.22 What is a potentiometer? Give its principle. 12113126

Q.23 Give uses of potentiometer. 12113127

UNIT 14

ELECTROMAGNETISM

MULTIPLE CHOICE QUESTIONS

1. One of the following quantities that is not affected by the magnetic field is

a) Moving charge 12114046

b) Change in magnetic flux

c) Current flowing in conductor

d) Stationary charge

2. What is the value of the current in a wire of 10cm long at the right angle to a uniform magnetic field of 0.5 Weber/m² when the force acting on the wire is 5N?

a) 1A b) 10A 12114047

c) 100A d) 1000A

3. Magnetic field is detected by 12114048

a) Ammeter b) Galvanometer

c) Avometer d) Magnetic compass

4. A magnetic compass will be deflected if it is kept near a 12114049

a) Charge in motion

b) Charge at rest

c) Both

d) None

5. If a current is passing through a wire, the magnet lines of force are 12114050

a) Parallel to the wire

b) Perpendicular to the wire

c) Inclined to the wire

d) concentric circles

6. The direction of lines of magnetic force can be found by 12114051

a) Right hand rule

b) Left hand rule

c) Hund’s rule

d) Left and right hand rules

7. If electric current flows from top towards the bottom through a wire then the direction of lines of force would be

a) Parallel to the wire 12114052

b) Perpendicular to the wire

c) Clockwise around the wire

d) Anticlockwise around the wire

8. If a current carrying solenoid is suspended freely it will 12114053

a) Be rotating

b) Come to rest in N-S direction

c) Vibrating like galvanometer needle

d) Comes to rest after rotation

9. A changing magnetic field produces

a) Electric current 12114054

b) Changing Electric field

c) Magnetic field

d) Conservative field

10. Electric current generates 12114055

a) Electric field b) Magnetic field

c) Nuclear field d) Gravitational field

11. Force on a current carrying conductor placed in a magnetic field is given by the relation 12114056

a) F = I (L ´ B) b) F = q ( L ´ B)

c) F = I (V ´ B) d) F = q (V ´ B)

12. A current carrying straight conductor is placed in a magnetic field parallel to it. The force experienced by the conductor is

a) F = BIL 12114057

b) F = BIL Sin q

c) F = BIL Cosq

d) F = 0

13. Two free parallel straight wires carrying currents in the opposite direction 12114058

a) Do not affect each other

b) Attract each other

c) Repel each other

d) Get rotated

14. Two free parallel straight wires carrying currents in the same direction 12114059

a) Repel each other

b) Attract each other

c) Do not affect each other

d) Get rotated

15. If the current passing through a wire in a magnetic field is doubled, the magnetic force would become 12114060

a) Six times b) Five times

c) Four times d) Twice

16. The number of magnetic lines of force passing through any surface is known as

a) Magnetism b) Flux 12114061

c) Magnetic flux d) Flux density

17. Total number of magnetic lines of force passing normally through unit area is called 12114062

a) Magnetism b) Flux

c) Magnetic flux d) Flux density

18. The SI unit of magnetic flux is 12114063

a) Weber b) Nm A^-1

c) N m^-1d) both a & b

19. The SI unit of magnetic induction or flux density is 12114064

a) Gauss b) Tesla

c) Ampere d) Weber

20. Magnetic flux will be maximum when

a) Angle between B and A is 45^o12114065

b) B lies perpendicular to the plane of area A

c) B lies parallel to the plane of area A

d) B is a null vector

21. A 0.50T field over an area of 2m² which lies at angle of 60^o to the field, then the magnetic flux is 12114066

a) 0.50 weber b) 0.75 weber

c) 2 weber d) 4 weber

22. The dot product of B and L around any closed path is equal to the product of permeability of free space and the current is known as 12114067

a) Faraday’s law

b) Coulomb’s law

c) Gauss’s law

d) Ampere’s circuital law

23. The ratio of a proton 12114068

a) Is equal to that of an electron

b) Is greater than that of an electron

c) Is smaller than that of an electron

d) May be smaller or greater

24. A long, tightly wound, cylindrical coil of wire is called 12114069

a) Toroid b) Inductor

c) Solenoid d) Oscilloscope

25. When a charged particle is projected perpendicular to uniform magnetic field, its trajectory (path) is 12114070

a) A helix b) Ellipse

c) Straight line d) A circle

26. A high speed graph plotting device is

a) Galvanometer 12114071

b) Cathode ray oscilloscope (CRO)

c) Voltmeter

d) Printer

27. Cathode ray oscilloscope works by deflecting beam of 12114072

a) Protons b) Neutrons

c) Electrons d) Positrons

28. The electron gun in cathode ray oscilloscope consists of 12114073

a) Grid

b) Three anodes

c) Indirectly heated cathode

d) All of above

29. If the magnetic field B makes an angle 90⁰ with the plane of the coil, the torque acting on the coil is given by 12114074

a) IBA Sin α b) IBA Cos α

c) NIBA Cos α d) zero

30. A coil having ‘N’ turns placed in the uniform magnetic field experiences a torque given by 12114075

a) BIN Sin α b) BIN Cos α

c) BIAN Cos α d) BIN tan α

31. The galvanometer can be made sensitive by making the factor 12114076

a) Large b) Small

c) Zero d) Constant

32. In order to increase the range of a voltmeter, the series resistance is 12114077

a) Increased b) Decreased

c) Kept constant d) Removed

33. Avometer is basically consists of 12114078

a) voltmeter b) Ohm-meter

c) Ammeter d) All of these

34. A commercial instrument for measuring currents, voltages and resistance is known as 12114079

a) Voltmeter b) Avo-meter

c) Ammeter d) Galvanometer

35. The sensitivity of a galvanometer is given by 12114080

(a) (b)

36. In order to increase the range of an ammeter the shunt resistance is: 12114081

(a) Decreased

(b) Increased

(d) Sometimes increased and sometimes decreased

37. To measure potential difference across a resistor, voltmeter is always a connected in: 12114082

(a) Series

(b) Parallel

(d) None of these

38. There are two hair springs present in pivoted type galvanometer. These are used: 12114083

a) To produce restoring torque

b) As current leads

c) To produce deflecting torque

d) Both A & B

39. A coil is placed in a radial magnetic field then the plane of the coil is: 12114084

a) At 60^o to the field

b) 180^o to the field

c) Perpendicular to the field

d) Parallel to the field

40. An electron is moving along the axis of a solenoid carrying a current which of the following is a correct statement about the electromagnetic force acting on the electron? 12114085

a) The force acts radially inwards

b) The force acts radially outwards

c) The force acts in the direction of motion

d) No force acts

41.When the coil of the galvanometer is in equilibrium then the deflecting couple is

a) Zero 12114086

b) Equal to the restoring couple

c) Greater than the restoring couple

d) Smaller than the restoring couple

42. Which one of the following is not an electromechanical instrument? 12114087

a) Galvanometer

b) Voltmeter

c) Ammeter

d) AC transformer and DC generator

43. Galvanometer is a very sensitive device with 12114088

a) Very low damping

b) Very high damping

c) No damping at all

d) Radial field disintegration

44. In moving coil galvanometer the pole faces of U-shaped magnet are made concave 12114089

a) To make the field radial

b) To increase the field

c) To weaken field

d) Both a and b

45. The work done by a magnetic field for revolving the charged particle q in a circular path will be 12114090

a) Fd b) Max

c) Negative d) Zero

46. The device known as low resistance galvanometer is 12114091

a) Ammeter b) Ohmmeter

c) Voltmeter d) Avometer

47. Ratio of magnetic force F_m and electric force F_e acting on a charge getting undflected through the field is 12114092

a) E/B b) B/E

c) 1 d) 0

SHORT ANSWERS

Q.1 In what direction are the magnetic field lines surrounding a straight wire carrying current that is moving towards you? 12114093

Q. 2 What kind of field / fields does/ do surround a moving a electric charge?

12114094

Q. 3 Why is B non-zero outside the solenoid? 12114095

Q. 4 Why is a voltmeter connected parallel to the points between which voltage is to be measured? 12114096

Q. 5 What is shunt resistance? 12114097

Q. 6 A wire is covered with a carpet. How will you find whether any current is flowing through the wire? 12114098

Q. 7 What is Dead Beat galvanometer?

12114099

Q. 8 What is Current Sensitivity of galvanometer? 12114100

Q. 9 What is Lorentz force? (Board 2015) 12114101

Q.10 What is velocity selector? 12114102

UNIT 15

ELECTRO MAGNETIC INDUCTION

MULTIPLE CHOICE QUESTIONS

1. The fact that emf produced by motion of a coil across a magnetic field was discovered by 12115059

a) Michael Faraday b) Henry

c) Orested d) Both a & b

2. The e.m.f. produced in the conductor when it moves across a magnetic field is called 12115060

a) Self emf b) Induced emf

c) Motional emf d) Mutual emf

3. What is induced when there is a relative motion between coil and the magnet?

12115061

a) Flux b) Potential

c) Energy d) emf

4. The value of the induced emf is directly proportional to the rate of change of

12115062

a) Flux b) potential

c) Force d) Work

5. The current produced when the conductor moves across a magnetic field is called

a) Conventional current 12115063

b) Induced current

c) Self current

d) Motional current

6. The phenomenon by which an induced emf is produced due to change of flux is called 12115064

a) Electric potential

b) Electrostatic induction

c) Electromagnetic induction

d) Electric polarization

7. The emf produced by motion of a conductor across a magnetic field is called: 12115065

a) Induced emf b) Self emf

c) Mutual emf d) Motional emf

8. The motional emf depends upon the

a) Length of a conductor 12115066

b) Strength of a magnetic field

c) Speed of the conductor

d) All of the above

9. If velocity of conductor moving in a magnetic field is zero then its motional emf will be 12115067

a) Zero b) vBL

c) qvB d) IBL

10. The induction heater operates on the principle of 12115068

a) Electrostatic induction

b) Electrostatic conduction

c) Electromagnetic radiation

d) Electromagnetic induction

11. The direction of induced current is always so as to oppose the change, which causes the current. This is the statement of 12115069

a) Faraday’s law b) Lenz’s law

c) Gauss’s law d) Joule’s law

12. Lenz’s law is consistent with 12115070

a) Law of conservation of energy

b) Law of conservation of charge

c) Law of conservation of momentum

d) Law of conservation of mass

13. Electromagnetic induction is exactly according to the law of conservation of

a) Charge b) Energy 12115071

c) Momentum d) Mass

14. The phenomenon in which a changing current in one coil induces an emf in other coil is called 12115072

a) Electromagnetic induction

b) Electrostatic induction

c) Mutual induction d) Self induction

15. Lenz’s law deals with the 12115073

a) Magnitude of induced current

b) Magnitude of induced emf

c) Direction of induced emf

d) Direction of induced current

16. The coil placed in the galvanometer circuit in the experiment of mutual induction is called 12115074

a) Primary b) Secondary

c) Potentiometer d) Thermistor

17. The ratio of average emf induced in the secondary coil to the time rate of change of current in the primary coil is known as

12115075

a) Self induction b) Self inductance

c) Mutual inductance d) Motional emf

18. SI unit of mutual inductance is called

a) Coulomb b) Farad 12115076

c) Henry d) Tesla

19. The SI unit of induced emf is 12115077

a) Volt b) Henry

c) Ampere d) Tesla

20. The ratio of average e.m.f. in the coil to the time rate of change of current in the same coil is called 12115078

a) Mutual induction

b) Mutual inductance

c) Capacitance

d) Self inductance

21. The SI unit of self inductance is called

a) Volt b) Farad 12115079

c) Henry d) Ampere

22. Self induced emf is also called 12115080

a) Motional emf

b) Thermistor

c) Electrostatic induction

d) Back emf

23. An inductor is a form of 12115081

a) Coil

b) Solenoid

c) Toroid

d) Both (a) and (b)

24. When number of turns in a coil is tripled, without any change in length of the coil, its self inductance becomes 12115082

a) One-third b) Three times

c) Six times d) Nine times

25. The work is stored in the inductor as

a) Electric potential energy 12115083

b) Elastic potential energy

c) Magnetic energy

d) Absolute potential energy

26. Energy stored per unit volume inside a solenoid is called 12115084

a) Charge density

b) Volume charge density

c) Surface charge density

d) Energy density

27. A device which converts mechanical energy into electrical energy is called

12115085

a) Motor

b) Vibrator

c) Heat generator

d) Current generator

28. The principle of electric generator depends on 12115086

a) Ohm’s law b) Lenz’s law

c) Coulomb’s law d) Faraday’s law

29. The working of A.C. generator is based upon the phenomenon of 12115087

a) Self induction

b) Electromagnetic induction

c) Mutual induction

d) Polarization

30. Alternating emf is produced by rotating a coil in 12115088

a) Gravitational field

b) Nuclear field

c) Magnetic field

d) Electric field

31. Split rings act as 12115089

a) Vibrator b) Resistor

c) Motor d) Commutator

32. Commutator was invented in 1934 by

a) Newton 12115090

b) Coulomb

c) Michael Faraday

d) William sturgeon

33. The brushes used in a generator are made up of 12115091

a) Graphite or Carbon

b) Iron or Nickel

c) Copper or iron

d) Steel or copper

34. If the plane of the generator coil is parallel to the field then e.m.f. induced in coil is 12115092

a) Zero b) Infinite

c) Maximum or one d) One or zero

35. The component in a generator which consumes electrical energy is called a

a) Coil b) Load 12115093

c) Capacitor d) Commutator

36. In transformer, number of turns in primary coil are 140 and that in secondary coil are 160. If current in primary is 8A then in secondary coil is

a) 2A b) 3A 12115094

c) 5A d) 7A

37. Identify which one is not the component of an A.C. generator 12115095

a) Magnet b) Commutator

c) Slip rings d) Armature

38. A device which converts electrical energy into mechanical energy is called 12115096

a) Transformer b) D.C. motor

c) D.C. generator d) A.C. generator

39. A.C. is converted into D.C. by 12115097

a) Transformer b) Motor

c) Capacitor d) Rectifier

40. If back emf in a motor decreases, then it will draw 12115098

a) More current b) Small current

c) No current d) Infinite current

41. A motor of zero back e.m.f. draws 12115099

a) Zero current b) Minimum current

c) Constant current

d) Maximum current

42. Transformer works on the principle of

a) Self induction 12115100

b) Back emf

c) Mutual induction

d) Right hand rule

43. The emf induced in 1mH inductor in which current change from 5A to 3A in 1msec is: 12115101

a) 2 × 10^-6V b) 8 × 10^-6V

c) 2 V d) 8V

44. A step up transformer is used on a 120V line to provide 240V. If the primary coil has 75 turns the number of turns in the secondary coil is: 12115102

a) 150 b) 1000

c) 500 d) 250

45. The inductance of a coil is proportional to: 12115103

a) its length

b) the number of turns

c) The resistance of the coil

d) The square of the number of turns

46. Production of induced emf in a coil is linked with 12115104

a) Nature of coil

b) Shape of coil

c) Flux through coil

d) Change in flux through coil

47. The current drawn by armature of DC motor is directly proportional to 12115105

a) Speed of motor

b) Torque

c) Voltage across terminals

d) None of these

48. The self inductance of the motor of an electric fan is 10H. in order to impart maximum power at 50Hz, it should be connected to a capacitance of 12115106

a) 8 μF b) 4 μF

c) 1 μF d) 6 μF

49. A capacitor is used to 12115107

a) Block DC current

b) Pass DC current

c) Open voltage source

d) Short voltage source

50. The mutual inductance of the pair of the coils depends upon 12115108

a) Current in coils

b) Material of the wires of the coils

c) Relative position and orientation of the coils

d) Rates at which the currents are changing

51. A step up transformer _______. 12115109

a) Step up the level of frequency

b) Step down the level of current

c) Step up level of power

d) Both a & b

52. If applied voltage of DC motor is 230 V, then back emf , for maximum power developed is : 12115110

a) 115 V b) 220 V

c) 230 V d) 460 V

53. The back emf of motor is proportional to

a) Speed of motor 12115111

b) Torque

c) Energy source

d) None of these

SHORT ANSWERS

Q. 1 In what three ways can a voltage be induced in a wire? 12115112

Q. 2 Does the voltage output of a generator change if its speed of rotation is increased? Explain. 12115113

Q. 3 Can a current carrying coil be used as a compass? Explain. 12115114

Q. 4 What are the similarities between a motor and a generator? What are the difference? 12115115

Q.5 What is the difference between an ideal transformer and real transformer?

12115116

Q. 6 How the fluctuations in the output of D.C generator can be reduced? 12115117

Q. 7 What is Eddy current? 12115118

Q. 8 What is Faraday’s law of electromagnetic induction? 12115119

Q. 9 What is Efficiency of a transformer? 12115120

Q. 10 What is meant by Armature?

12115121

UNIT 16

ALTERNATING CURRENT

MULTIPLE CHOICE QUESTIONS

1. The frequency of alternating current in Pakistan is 12116048

a) 50Hz b) 100 Hz

c) 220 Hz d) 400 Hz

2. The current whose direction is changed after equal intervals of time is 12116049

a) Direct current

b) Alternating current

c) Electronic current

d) None of above

3. The root mean square value of alternating voltage is 12116050

a) 0.707 V_o b) 0.303 V_o

c) 0.505 V_o d) 0.777 V_o

4. The instantaneous value of sinusoidal voltage is 12116051

a) V_o sin 2pt b) V_o sin 2pft

c) V_o cos 2pft d) V_o sin pt

5. The voltage which changes its polarity with time is called 12116052

a) Direct voltage

b) r.m.s. Voltage

c) Alternating voltage

d) Peak voltage

6. The highest value reached by the voltage or current in one cycle is called 12116053

a) Peak value

b) Minimum value

c) Instantaneous value

d) Absolute value

7. The graph between alternating voltage and time is 12116054

a) Sine curve b) Ellipse

c) Straight line d) Tangent curve

8. The current which flows through the circuit in one direction is 12116055

a) Eddy current

b) Direct current

c) Alternating current

d) None of these

9. In A.C. circuit, the current and voltage are controlled by 12116056

a) Resistor only b) Inductor only

c) Capacitor only d) All of above

10. In resistive circuit 12116057

a) Current leads the voltage

b) Current lags the voltage

c) Current and voltage are in phase

d) All of above

11. The phase angle at +ve peak is 12116058

a) b) p

c) d) 2p

12. The phase angle at –ve peak is 12116059

a) b)

c) 2p d) p

13. The power in the resistive circuit 12116060

a) P = VI b) P = I² R

c) P = d) All of above

14. The instantaneous charge on a capacitor when connected with AC source. 12116061

a) CV b) CV_o sin wt

c) C V_o tan wt d) CV_o cos wt

15. In a capacitor circuit 12116062

a) Current lags the voltage by p/2

b) Current leads the voltage by p/2

c) Current and voltage are in phase

d) Current leads voltage by 270^o

16. A device through which D.C cannot flow is called 12116063

a) Capacitor b) Inductor

c) Generator d) Motor

17. The reactance of a capacitor is 12116064

a) wC b)

c) d)

18. The opposition offered by a capacitor to the flow of an A.C is called 12116065

a) Capacitance

b) Resistance

c) Capacitive Reactance

d) Inductance L

19. In capacitive circuit, at high frequency the reactance will be 12116066

a) Low b) High

c) Zero d) Medium

20. In capacitive circuit at high frequency the current will be, 12116067

a) Small b) Large

c) Infinite d) Zero

21. In inductive circuit 12116068

a) Current lags the voltage by p/2

b) Current leads the voltage by p/2

c) Current leads the voltage by 270^o

d) Current and voltage are in phase

22. The opposition offered by an inductor in A.C is 12116069

a) Impedence b) Resistance

c) Capacitance d) Inductive reactance

23. In an inductive circuit at low frequency the current will be 12116070

a) Zero b) Large

c) Small d) Infinite

24. The behaviour of resistance in A.C circuit is independent of 12116071

a) Power b) Current

c) Voltage d) Frequency

25. The power dissipation in a pure inductor is 12116072

a) Zero b) Small

c) Large d) Infinite

26. The value of inductive reactance is given by the relation 12116073

a) 2pfL b) 4pfL

c) d)

27. The inductive reactance is directly proportional to 12116074

a) Capacitance b) Inductance

c) Frequency of A.C d) Both b and c

28. The combined opposition of resistance and reactance in an A.C circuit is called:

12116075

a) Resistance b) Impedence

c) Capacitance d) Conductance

29. The impedence of R-C series, circuit is

12116076

a) b)

c) d)

30. The impedence is expressed as 12116077

a) Z = VI b) Z = I/V

c) Z = V/I d) Z = V² I

31. In R-C series circuit the current leads the voltage by 12116078

a) q = Tan^–1 (CR)

b) q = Tan^–1 ()

c) q = Tan^–1 ()

d) q = Tan^–1 ()

32. The ratio of rms value of the applied voltage to rms value of alternating current is called: 12116079

a) Impedence b) Capacitance

c) Conductance d) Resistance

33. The impedence of R-L series circuit is 12116080

a) R² + (L)²b)

c) L d)

34. In the relation P = IV Cos q, Cos q is called 12116081

a) Phase angle b) Minimum factor

c) Power factor d) Maximum factor

35. The circuit in which current and voltage are in phase, the power factor is 12116082

a) Zero b) 1

c) Negative d) Infinity

36. The resonance frequency in R-L-C series circuit is 12116083

a) b)

c) d)

37. When X_L = X_C, this condition is called

12116084

a) Null b) Balanced

c) Resonance d) Absolute

38. In R-L-C series resonance circuit the impedence is 12116085

a) Minimum b) Maximum

c) Zero d) Infinite

39. In RLC series circuit the current at resonance frequency is 12116086

a) Minimum b) Maximum

c) Zero d) Infinite

40. At resonance, the impedance of parallel circuit is 12116087

a) Maximum b) Minimum

c) Infinite d) Zero

41. In parallel resonance circuit the current at resonance is 12116088

a) Zero b) Maximum

c) Minimum d) Infinite

42. The resonance frequency for parallel circuit is 12116089

a) b) 2pLC

c) d)

43. The number of coils in three phase A.C generator are 12116090

a) One b) Two

c) Three d) Four

44. The changes of electric and magnetic flux produce 12116091

a) Electromagnetic waves

b) Sound waves

c) Longitudinal waves

d) Material waves

45. The electric field, magnetic field and direction of propagation are mutually.

12116092

a) Perpendicular b) Parallel

c) Anti parallel d) None of these

46. Electromagnetic waves consist of 12116093

a) Electric field b) Magnetic field

c) Electric and Magnetic field

d) Nuclear field

47. Electromagnetic waves are 12116094

a) Longitudinal b) Transverse

c) Circular d) Stationary

48. Which of the following have smaller wave length? 12116095

a) g-rays b) X-rays

c) Radio waves d) Ultraviolet waves

49. High frequency radio waves are called:

a) Complex waves 12116096

b) Modulated waves

c) Carrier waves

d) Polarized waves

50. Electromagnetic waves were discovered by 12116097

a) Hertz b) Newton

c) Einstien d) Maxwell

51. Which of the following have longest wavelength? 12116098

a) Radio waves b) X-rays

c) g -rays d) Infrared waves

52. In free space, the speed of electromagnetic waves is 12116099

a) 3 x 10⁵ m/sec b) 3 x 10⁵ km/sec

c) 3 x 10^–8 m/sec d) 3 x 10¹⁰ m/sec

53. The combining of low frequency signal and high frequency radio waves is called

12116100

a) Rectification b) Amplification

c) Modulation d) Polarization

54. The frequency range of amplitude modulated wave is 12116101

a) 540 kHz ® 1600 kHz

b) 88 kHz ® 108 kHz

c) 540 MHz ® 1600 MHz

d) 88 MHz ® 108 MHz

55. The frequency range of F.M waves is in the range. 12116102

a) 88 kHz ® 108 kHz

b) 88 MHz ® 108 MHz

c) 540 kHz ® 1600 kHz

d) 540 MHz ® 1600 MH

56. The reactance of an inductor at 50 Hz is 10W. Its reactance at 100 HZ is 12116103

a) 2.5 W b) 5 W

c) 10 W d) 20 W

57. The current and voltage in an A.C circuit are respectively given by I = I_o sin wt and V = V_o sin wt. The power consumed in the circuit is 12116104

a) V_o I_o b)

c) d) Zero

58. In FM, the change in carrier frequency is proportional to 12116105

a) Angle b) Frequency

c) Amplitude d) Tone

59. A circuit has resistance of 12 ohm and impedance of 15 ohm. The power factor of the circuit will be 12116106

a) 0.4 b) 0.8

c) 1.25 d) 125

60. A carrier signal has 12116107

a) Constant amplitude

b) High frequency

c) Varying amplitude

d) Information content

61. What aspect of the carrier is changed by modulation? 12116108

a) Frequency

b) Phase

c) Amplitude

d) Depends on the type of modulation

62. Two different signals can be coherent if they 12116109

a) Have same amplitude

b) Are both sine waves of different frequencies

c) Originate in same physical equipment

d) Have same frequency

63. The factor 0.707 for converting peak to rms applies only to 12116110

a) Square waves

b) Saw tooth waves

c) Sine waves

d) Triangle waves

64. What will be the resonance frequency of the circuit if L of 3μH and C of 40 pF are connected in series? 12116111

a) 14.5 kHz

b) 14.5 MHz

c) 145 MHz

d) 145 kHz

65. The root mean square value (rms) is the square root of the average value of 12116112

a) V or I

b) V or R

c) V² or I²

d) V² or R²

SHORT ANSWERS

Q.1 What is alternating current? 12116113

Q.2 In A.C. How many circuit elements control the current? 12116114

Q.3 Define impedence. 12116115

Q.4 What is capacitive reactance? 12116116

Q.5 What is the effect of frequency on X_C and X_L? 12116117

Q.6 What are relations for impedencein R-L and R-C series circuits? 12116118

Q.7 What is power loss in A.C Circuit?

12116119

Q.8 What is resonance frequency? 12116120

Q.9 What is the current in RLC parallel resonance circuit? 12116121

Q.10 How many coils are used in three phase A.C source? 12116122

Q.11 What is a choke? 12116123

Q.12 What is modulation? 12116124

UNIT 17

PHYSICS OF SOLIDS

MULTIPLE CHOICE QUESTIONS

1. A solid is in which atoms are in a regular order is called 12117030

a) Crystalline solid

b) Amorphous solid

c) Polymeric solid

d) Glassy solid

2. Which of the following is a crystalline solid? 12117031

a) Copper b) NaCl

c) Zirconia d) All of these

3. Which of the following is polymeric solid? 12117032

a) Nylon b) Plastic

c) Polythene d) All of these

4. A solid in which there is no regular arrangement of molecules is called 12117033

a) Amorphous b) Crystalline

c) Copper d) None of these

5. Which class of material would you classify Nylon? 12117034

a) Fibres b) Polymer

c) Ceramics d) Glass

6. The deformation of body is the change in its

a) Shape b) Length 12117035

c) Area d) All of these

7. A smallest three dimensional part of a crystal lattice is called 12117036

a) A particle b) A molecule

c) A unit cell d) An atom

8. The pattern of NaCl particles have a

12117037

a) Triangular b) Square

c) Cubic d) Rectangular

9. When stress changes the shape then it is called 12117038

a) Shear stress

b) Tensile stress

c) Compressive stress

d) Volumetric stress

10. The unit Nm^–2 is also called 12117039

a) coulomb b) newton

c) pascal d) ampere

11. Stress is defined as 12117040

a) F/A b) F/A²

c) A/F d) F´A

12. S.I unit of stress is 12117041

a) N/m b) N m

c) Nm^–2 d) newton

13. The ability of a body to return to its original shape is called 12117042
a) Plasticity b) Elasticity

c) Strain d) Stress

14. The strain due to tensile stress is 12117043

a) Compressive strain

b) Shear strain

c) Volumetric strain

d) Tensile strain

15. S.I unit of strain 12117044

a) newton b) N m^–2

c) pascal d) no unit

16. When stress changes the length of a body it is called 12117045

a) Tensile stress b) Shear stress

c) Compressive stress d) Yield stress

17. The deformation of a solid when stress is applied is called 12117046

a) Strain b) Elasticity

c) Rigidity d) Pressure

18. The S.I Unit of Modulus elasticity is

12117047

a) pascal b) coulomb

c) ampere d) none of these

19. The volumetric strain is 12117048

a) DV/V_o b) V_o/DV

c) DV/t d) None of these

20. Young’s Modulus is given by 12117049

a) (F/A) (DV/V) b) (F/A) ()

c) (FA) () d) (F/A) (DV)

21. The ratio of shear stress to shear strain is called 12117050

a) Shear modulus

b) Young’s Modulus

c) Bulk Modulus d) None of these

22. The ratio of stress to volumetric strain is called 12117051

a) Shear Modulus

b) Young’s Modulus

c) Bulk Modulus

d) Modulus of elasticity

23. The dimension of strain is 12117052

a) [L] b) [ML²T^–2]

c) [M L^–1 T^–2] d) Dimensionless

24. The substance which break just after elastic limit 12117053

a) Ductile b) Brittle

c) Soft d) Hard

25. The substance which undergo plastic deformation until break is 12117054

a) Brittle b) Ductile

c) Hard d) Soft

26. When stress is increased beyond elastic limit and material is permanently changed this property is 12117055

a) Permanent stress b) Elasticity

c) Yield strength d) Plasticity

27. The maximum stress that a body can tolerate is called 12117056

a) UTS b) Permanent stress

c) Elastic strength d) Plastic stress

28. Value of stress beyond which body is permanently deformed is called 12117057

a) Yield stress b) Maximum stress

c) Minimum stress d) Shear stress

29. The strain energy in a deformed material is 12117058

a) b)

c) d)

30. The substances of conductivity of the order of 10^–6 – 10^–4 (Wm)^–1 are 12117059

a) Insulators

b) Super conductors

c) Semiconductors

d) Good conductors

31. Substances of conductivity between

10^–10 ¾ 10^–20 (n m )^–1 are 12117060

a) Insulators

b) Semiconductors

c) Super conductors

d) Good conductors

32. Good conductors have conductivity of the order of 12117061

a) 10^–10 (Wm)^–1 b) 10^–7 (Wm)^–1

c) 10⁷ (Wm)^–1 d) 10^–9 (Wm)^–1

33. A band which is vacant or partially filled is

a) Conduction band 12117062

b) Forbidden band

c) Valance band

d) Filled band

34. The band above the valance band is called 12117063

a) Conduction band b) Filled band

c) Forbidden band d) Occupied band

35. The process of addition of impurity in pure semiconductor is 12117064

a) Doping b) Radiating

c) Mixing d) Insulating

36. Pure semiconductors silicon and germanium are 12117065

a) Extrinsic b) Intrinsic

c) Insulator d) Diodes

37. A doped semiconductor is called 12117066

a) Extrinsic b) Intrinsic

c) Insulator d) Conductor

38. Conductivity of semi conductor is increased by 12117067

a) Decrease of temperature

b) By keeping temperature constant

c) Increase of temperature

d) none of above

39. In a P-type semiconductor the charge carriers are 12117068

a) Electrons b) Holes

c) Protons d) Neutrons

40. In the N-type semiconductor the charge carriers are 12117069

a) Holes b) Neutrons

c) Protons d) Electrons

41. An alloy composed of copper, manganese and nickel is known as 12117070

a) Manganin b) Nichrome

c) Alnico d) German silver wire

42. Minority carriers in N-type are 12117071

a) Holes b) Electrons

c) Neutrons d) Protons

43. A P-type crystal is electrically 12117072

a) Negative b) Positive

c) Neutral d) None of these

44. A N-type crystal is electrically 12117073

a) Negative b) Positive

c) Neutral d) All of these

45. Donor impurities are 12117074

a) Germanium, Silicon

b) Indium, Boron

c) Antimony, Arsenic

d) Sodium, Carbon

46. A moving hole in a diode behave as

a) Negative charge 12117075

b) Positive charge

c) Neutral

d) positive and negative charge

47. The temperature at which material show super conductivity is 12117076

a) Super temperature

b) Critical temperature

c) Kelvin temperature

d) Absolute temperature

48. First super conductor was discovered by

a) Kelvin b) Hertz 12117077

c) Einstein d) Kamerlingh Ornes

49. The first super conductor was discovered in 12117078

a) 1961 b) 1911

c) 1851 d) 1811

50. The source of magnetism of an atom is

a) Electrons b) Protons 12117079

c) Holes d) Neutrons

51. The most suitable metal for making permanent magnet is 12117080

a) Iron b) Steel

c) Silver d) Copper

52. The magnetism lags behind the magnetizing current is called 12117081

a) Coercivity b) Retentivity

c) Saturation d) Hysteresis

53. The energy dissipated in magnetizing and demagnetizing is called 12117082

a) Saturation b) Retentivity

c) Coercivity d) Hysteresis loss

54. When current is zero but material still remains magnetized this property is called

a) Saturation b) Retentivity 12117083

c) Hysterisis d) Cohesive

55. The temperature at which material lose its orderliness due to increase of thermal vibration is 12117084

a) Absolute temperature

b) Critical temperature

c) Curie temperature

d) Super temperature

56. The substance in which atoms do not form magnetic dipoles are 12117085

a) Crystals b) Diamagnetic

c) Paramagnetic d) Ferromagnetic

57. The substance in which magnetic field due to spin and orbital motion of electronic is such that atom becomes tiny magnetic dipole is: 12117086

a) Paramagnetic b) Diamagnetic

c) Ferromagnetic d) Crystal

58. The substance in which magnetic field due to spin and orbital motion of electrons in an atom is such that they cancel each other then it becomes 12117087

a) Paramagnetic b) Diamagnetic

c) Ferromagnetic d) Conductor

59. The energy band which lies in between valence and conduction band are called.

a) Conduction band 12117088

b) Valance band

c) Permissible energy band

d) Forbidden energy band

60. The force in N, required to stretch a steel wire of 1cm² in cross section to double its length is (Y=2´10¹¹ N/m²) 12117089

a) 1´10⁷ b) 2´10¹¹

c) 2´10⁷ d) 1´10¹¹

61. A cable that can support a load of 800 N is cut into two equal parts. The maximum load that can be supported by either part is: 12117090

a) 100 N b) 400 N

c) 800 N d) 1600 N

62. a force F is needed to break a copper wire having radius R. The force needed to break a copper wire of same length and radius 2 R will be. 12117091

a) F/2 b) 2F

c) 4 F d) F/4

63. A wire elongates by l mm when a load W is hanged from it. If the wire goes over a pulley and two weight W each are hung at the two ends, the elongation of the wire will be (in mm): 12117092

a) Zero b) l / 2

c) l d) 2 / l

SHORT ANSWERS

Q.1 Whether atoms, ions or molecules in a crystalline solid are static? 12117093

Q.2 What is meant by Amorphous?

12117094

Q.3 What is meant by Cohesive Force?

12117095

Q.4 What is meant by Deformation of solids? 12117096

Q.5 Define Elasticity. 12117097

Q.6 Define yield point. 12117098

Q.7 What are ductile substance? 12117099

Q.8 What are brittle substance? 12117100

Q.9 What are semiconductors? 12117101

Q.10 What is meant by doping? 12117102

Q.11 What is hole? 12117103

Q.12 What is valance band? 12117104

Q.13 What is conduction band? 12117105

Q.14 What is super conductor? 12117106

Q.15 What is domain? 12117107

Q.16 What is curie temperature? 12117108

Q.17 What is coercive current? 12117109

UNIT 18

ELECTRONICS

MULTIPLE CHOICE QUESTIONS

1. N-type germanium is obtained by doping intrinsic germanium with 12118044

a) Trivalent impurity atoms

b) Tetravalent impurity atoms

c) Pentavalent impurity atom

d) None of above

2. P-type germanium is obtained by doping intrinsic germanium with 12118045

a) Trivalent impurity atoms

b) Tetravalent impurity atoms

c) Pentavalent impurity atoms

d) None of above

3. Both Germanium and Silicon belong to group 12118046

a) III b) IV

c) V d) I

4. Which one of the following is not a semi-conductor? 12118047

a) Silicon b) Germanium

c) Copper d) Gallium Arsenide

5. A p-n junction diode cannot be used as:

12118048

a) An amplifier b) Rectifier

c) A detector d) None of these

6. With rise of temperature the resistivity of a semi-conductor 12118049

a) Increases linearly

b) Decreases exponentially

c) Increases exponentially

d) Decreases linearly

7. Conversion of A.C. into D.C is called

12118050

a) Modulation b) Rectification

c) Amplification d) All of these

8. For rectification we use 12118051

a) Choke b) Diode
c) Transformer d) Capacitor

9. The atomic number Z of silicon is 12118052

a) 13 b) 14

c) 12 d) 16

10. The atomic number Z of germanium is

a) 30 b) 32 12118053

c) 26 d) 28

11. Acceptor impurities donate 12118054

a) Electrons b) Holes

c) Both a and b d) None of these

12. The p-n junction on forward – biasing act as a 12118055

a) High resistor b) Capacitor

c) Low resistor d) Inductor

13. A photodiode is usually made from 12118056

a) Bismuth b) Antimony

c) Silicon d) None of these

14. Ga As P and Ga As are the compound of semi-conductor used in 12118057

a) Photodiode

b) Light emitting diode

c) Photo voltaic cells

d) All of these

15. The width of depletion region of a junction 12118058

a) Decreases with light doping

b) Increases with heavy doping

c) Is independent of applied voltage

d) Increases with reverse biasing

16. Photo diode is used in 12118059

a) Detection

b) Automatic switching

c) Optical fiber Communication

d) All

17. Transistors can be used as: 12118060

a) Amplifier b) Switch

c) Oscillator d) All of these

18. In a half rectification the diode conducts during 12118061

a) Both half cycles b) Positive half

c) Negative Half d) One half input

19. Operational amplifier can be used as:

a) Comparator 12118062

b) Inverting amplifier

c) Non-inverting amplifier

d) All

20. The especially designed semiconductor diodes used as indicator lamps in electronic circuits are: 12118063

a) The switch

b) The light emitting diode

c) The photo diodes

d) Solar cells

21. The central region of transistor is called

a) Collector b) Base 12118064

c) Emitter d) Cathode

22. In manufacturing of transistor, usually

12118065

a) Emitter is smaller than collector

b) Base is smaller than both emitter and collector

c) Impurity in emitter is more than that of collector

d) All of above

23. The current gain of transistor whose base current is 100 mA and collector current is 100mA will be 12118066

a) 10^-3 b) 10³

c) 100 d) 1

24. Transistor is usually used as switch in:

a) Electric motor 12118067

b) Electric generator

c) Transformer

d) Computer

25. An amplifier circuit integrated on a silicon chip and enclosed in a small capsule is called 12118068

a) Diode b) Inductor

c) Amplifier d) Operational amplifier

26. The numbers of input terminals of an ordinary Op-amplifier are: 12118069

a) Two b) Three

c) Four d) Infinite

27. Which of the following are not the characteristics of an OP-amplifier? 12118070

a) It has a very high input resistance

b) It has very low output resistance

c) It has a very low open loop gain

d) All of above

28. The gain ‘G’ of non-inverting amplifier can be expressed as: 12118071

a) G = b) G =1 +

c) G = d) G = 1-

29. The gain of inverting amplifier can be expressed as: 12118072

a) G = b) G =1 +

c) G = d) G = 1 -

30. The gain of an inverting amplifier having external resistance R₁ = 50kW and

R₂ = 200 kW will be 12118073

a) -0.25 b) 2

c) -2 d) -4

31. Input resistance of a Op-amp is the resistance between 12118074

a) The positive and negative outputs

b) Positive and negative inputs

c) Output terminal and grounded

terminal

d) The two positive out puts

32. LDR means 12118075

a) Low degree radiation

b) Low degree resistance

c) Light dependent resistance

d) None of these

33. Automatic functioning of street light can be done by the use of 12118076

a) Rectifier b) Inductor

c) Comparator d) Switch

34. A system which deals with quantities or variables which have only two discrete values or states is called 12118077

a) Logic gates b) Set

c) Digital system d) A.C. quantities

35. Logic gates can implement 12118078

a) OR operation only

b) NOT operation only

c) AND operation only

d) All of above

36. OR gate can only display an out put when one of its input must be at 12118079

a) 0 b) 1

c) 0 or 1 d) None of these

37. A NOT gate can be used as an inverter to change 12118080

a) 1 to 0 only

b) 0 to 1 only

c) 1 to 0 and 0 to 1 only

d) None of these

38. NOR gate is used to invert the output of

a) NAND gate b) AND gate 12118081

c) NOT gate d) OR gate

39. Exclusive NOR gate can be obtained by inverting the output of 12118082

a) XOR gate b) NOT gate

c) AND Gate d) None of these

40. A device which converts some physical quantities into voltage is called 12118083

a) Transistor b) Sensor

c) Diode d) Amplifier

41. Tick the sensor among the following 12118084

a) LDR b) Thermistor

c) Photo diode d) All of above

42. An OP-AMPs can amplify:

12118085

a) D.C b) A.C

c) Both A.C & D.C d) None of these

43. In full wave rectifier operation from 50 Hz main frequency, the fundamental frequency of ripple would be: 12118086

a) 100 Hz b) 25 Hz

c) 50 Hz d) 5052 Hz

44. What input values will cause AND logic gate to produce a high output: 12118087

a) At least one point is high

b) All inputs are high

c) At least one input is low

d) All inputs are low

45. OR Logic gate: 12118088

a) Implements logic subtraction

b) Is equivalent to a series switches in a circuit

c) Is a combination of two AND logic gates

d) Is equivalent to switches in parallel in a circuit

a. SHORT ANSWERS

Q.1 Differentiate between P-type and n-type substances? 12118089

Q.2 What is a p -n junction? 12118090

Q.3 What is the potential barrier of silicon and germanium? 12118091

Q.4 Differentiate between forward biasing and reverse biasing of a p-n junction? 12118092

Q.5 What is rectification? 12118093

Q. 6 Write the names of some special diode? 12118094

Q.7 Mention some important applications of photo diodes? 12118095

Q.8 Differentiate between a half wave and full wave rectification? 12118096

Q.9 What is the behaviour of the diode during rectification of negative cycle of an A.C? 12118097

Q.10 What is the working principle of a LED? 12118098

Q.11 What is transistor? 12118099

Q.12 What is meant by current gain of a transistor? 12118100

Q.13 Find the current gain “ b” of a transistor whose collector current is 100mA while base current is 100mA? 12118101

Q.14 What is the voltage gain of a transistor? 12118102

Q.15 Draw a neat diagram of an OP-amp? 12118103

Q.16 What is open loop gain of an OP-amp? 12118104

Q.17 Write some important uses of OP-amplifier. 12118105

Q.18 What is the difference between input and output resistances of an OP-amp? 12118106

Q.19 How a “XNOR” gate is made from a given XOR gate? 12118107

Q.20 What is the function of a sensor? Give at least one example. 12118108

Q.21 Find the gain of investing amplifier of external resistances R₁ = 50KW and

R₂ = 100 KW 12118109

Unit	MODERN PHYSICS
19

MULTIPLE CHOICE QUESTIONS

1. Which one of the following waves requires a material medium for their propagation? 12119066

a) Light waves

b) X– rays

c) g-rays

d) Sound waves

2. Which one of the following scientists regarded light as electromagnetic waves? 12119067

a) Newton b) Galileo

c) de Broglie d) Maxwell

3. Which one of the following physical quantities is independent of relativistic speed? 12119068

a) Mass b) Length

c) Time d) Charge

4. Relativistic velocity is of the order of

a) of the velocity of light 12119069

b) of the velocity of light

c) of the velocity of light

d) of the velocity of light

5. The energy ‘E’ is equivalent to mass given by 12119070

a) Ec² b)

c) d)

6. The mass of an object will be doubled at the speed 12119071

a) 2.6 ´ 10⁷ m/s

b) 1.6 ´ 10⁸ m/s

c) 2.6 ´ 10⁸ m/s

d) None of these

7. The length of rod at rest as measured by an observer moving parallel to it with relativistic speed is given by, 12119072

b) = _O

d) _O =

8. A rod at rest appears to an observer just a mere point when he moves across it as speed 12119073

a) Equal to the speed of light

b) Double the speed of light

c) Three-fourth the speed of light

d) None of the above

9. 0.001 kg mass will be equivalent to

a) 2.50 Giga watt hour 12119074

b) 25.00 Giga watt hour

c) 0.26 Giga watt hour

d) 0.25 Giga watt hour

10. Which one of the following radiations has the most energetic photon? 12119075

a) T.V. waves b) Micro waves

c) X-rays d) g - rays

11. A non-inertial frame of reference: 12119076

a) Moves with same acceleration

b) Is always rest on earth

c) Moves with uniform velocity

d) All of the above

12. The SI unit of Planck’s constant is 12119077

a) joule – sec^-1 b) joule – sec^-2

c) joule – sec d) joule – sec²

13. The dimensional representation of Planck’s constant is same as that of:

a) Angular momentum 12119078

b) Momentum

c) Torque

d) Energy

14. If the distance of an electric-lamp from a photo cell is continuously increased, the photo electric current (I) varies with distance (d) as, 12119079

a) I d² b) I d

c) I d) I

15. The linear momentum of a photon is

a) Zero b) 12119080

c) d)

16. A device based on photo electric effect is called 12119081

a) Photo sensitive b) Photo diode

c) Photo synthesis d) Photo cell

17. A Compton shift in wavelength is given by 12119082

d) None of the above

18. Compton wavelength is given by 12119083

a) b)

c) d)

19. The phenomena of pair production occurs only when the energy of incident photon is at least equal to 12119084

a) 10.2 MeV b) 1.02 MeV

c) 1.02 eV d) 0.102 MeV

20. If energy of incident photon is greater than the rest mass energy of electron positron pair, the surplus energy is shared by the pair as, 12119085

a) Potential energy b) Thermal energy

c) Electronic energy d) Kinetic energy

21. Which one of the following quantities is conserved in pair production? 12119086

a) Energy b) Charge

c) Linear momentum d) All

22. The presence of anti-matter was predicted by 12119087

a) P.A.M Dirac b) Anderson

c) Einstein d) Chamberlain

23. Which of the following phenomena provides a convincing proof for wave nature of radiation 12119088

a) Interference b) Diffraction

c) Polarization d) All of these

24. The concept of matter waves was introduced by 12119089

a) Davisson and Germer

b) de Broglie

c) Einstein

d) Schrodinger

25. The wavelength of the wave associated with a moving object is given by 12119090

a) b)

c) d)

26. The wavelength of the wave associated with the moving object is 12119091

a) Directly proportional to the

accelerating voltage

b) Directly proportional to the square of

accelerating voltage

c) Inversely proportional to the square

root of accelerating voltage

d) Inversely proportional to the

accelerating voltage

27. An electron accelerated in a P.D. of one volt has a wave associated with it of wavelength 12119092

a) 123 b) 1.23

c) 12.3 d) 0.123

28. Uncertainty principle was presented by

12119093

a) Dirac b) de Broglie

c) Shrodinger d) W. Heisenberg

29. Pair production can be studied with 12119094

a) Ultraviolet rays b) X-rays

c) Microwaves d) g-rays

30. Stopping potential for a metal surface in case of photo electric emission depends on:

12119095

a) The threshold frequency for the metal

surface

b) The intensity of incident light

c) The frequency of incident light and work function of the metal surface

d) All of the above

31. In Compton Effect 12119096

a) The frequency of scattered photon is smaller than the frequency of incident photon

b) The wavelength of scattered photon is

greater than the wavelength of incident

photon.

c) The momentum of electron

increases

d) All the above

32. In the annihilation of matter the number of photons produced is 12119097

a) One b) Two

c) Three d) Four

33. In annihilation of matter the photons produced fly off at the speed of 12119098

a) Light

b) Sound

c) Twice the speed of light

d) None of the above

34. Select the alternative from of uncertainty principle from the following 12119099

a) Dl = (1- Cos)

b) DE.Dt » h

c) mc² = hf

d) mc =

35. Positron was discovered by 12119100

a) J. J. Thomson b) Millikan

c) Anderson d) Dirac

36. de Broglie’s relation for matter waves was experimentally verified by: 12119101

a) Davisson b) Germer

c) G.P. Thomson d) All of these

37. Which one of the following phenomena can be studied with g-rays? 12119102

a) Photoelectric effect

b) Compton effect

c) Pair production

d) All of the above

38. Light waves can cause photoelectric emission in 12119103

a) Metals

b) Sodium

c) Insulators

d) None of these

39. The wave property of billiard ball

a) Can be observed 12119104

b) Cannot be observed

c) Cannot be said

d) None of these

40. A non-inertial frame of reference is that which 12119105

a) Remains at rest

b) Moves with uniform velocity

c) Is acted upon by some unbalanced force

d) All of above

41. The theory of relativity was proposed in

a) 1920 b) 1915 12119106

c) 1905 d) 1895

42. If a space craft of rest length ‘’ is moving with a speed equal to speed of light, then its relativistic length ‘’ will be 12119107

a) = _o b) =

c) = 0 d) All of these

43. If a material object moves with the speed of light ‘c’ its mass becomes 12119108

a) equal to its rest mass

b) Four times of its rest mass

c) Double of its rest mass

d) Infinite

44. A body will behave as an “ideal black body” when it acts as: 12119109

a) A perfect absorber

b) A perfect radiator

c) A body to have absorption power equal to one

d) All of the above

45. Black body radiations depends upon

12119110

a) The shape and nature of the body

b) The velocity of radiations and colour

of the body

c) The temperature of the body

d) All of the above

46. If h is the Planck constant, then ħ is:

a) 2πh b) 2h 12119111

c) h/2 d) h/2π

47. The radiations emitted by human body lies in 12119112

a) Infrared region

b) Ultraviolet region

c) Visible region

d) None of the above

48. The emission of number of photo electrons depends upon 12119113

a) The colour of the body

b) The frequency of incident light

c) The intensity of light

d) All of the above

49. The minimum energy required to eject an electron from a metal surface is called

a) Intensity 12119114

b) Threshold frequency

c) Work function d) Photo energy

50. The minimum frequency required to eject electrons from a metallic surface is called

a) Critical frequency 12119115

b) Peak value of frequency

c) Threshold frequency

d) Photo frequency

51. The stopping voltage for a certain metal is 100 volts, then the Maximum K.E of electron is 12119116

a) 100 J b) 1.6 ´ 10^-17 J

c) 1000 eV d) 1.6 ´ 10¹⁷ eV

52. Light of wavelength 50 ´ 10^-8m is incident on a metal surface to eject photoelectrons. The energy of incident photon is: 12119117

a) 4 ´ 10^-19 J b) 4 ´ 10^-19 eV

c) 50 ´ 10^-8J d) 50 ´ 10^-8eV

53. The reverse phenomena of photoelectric effect is called 12119118

a) Photo voltaic effect

b) Emission of X-rays

c) Radio activity

d) None of the above

54. If 2m_oc² is the total energy of the pair of electron and positron then the energy of each will be 12119119

a) 0.51 MeV b) 1.02 MeV

c) 0.52 J d) 1.02 J

55. The concept that particles can behave like waves was given by 12119120

a) Compton b) de-Broglie

c) G.P. Thomson d) Germer

56. The de-Broglie wave length is 12119121

a) Proportional to its momentum

b) Proportional to its energy

c) Inversely proportional to its energy

d) Inversely proportional to its

momentum

57. Noble prize was awarded to de-Broglie for his work on particle nature of light in

a) 1929 b) 1937 12119122

c) 1905 d) 1915

58. Uncertainty arises due to the 12119123

a) Human error b) Compton effect

c) Dual nature of light

d) None of the above

59. The product of uncertainties of two physical observables must be approximately equal to

a) Coulomb’s constant K 12119124

b) Ryd berg’s constant R

c) Planck’s constant

d) All of the above

60. A three dimensional image is obtained by

a) Electron microscope 12119125

b) Scanning electron microscope

c) Magnetic imaging

d) None of these

61. For confinement of electron in a box of radius 10^-14m, the electron speed:

a) 10⁷ m/s 12119126

b) Should be greater than speed of light

c) = 0.6c

d) None of these

62. Rest mass of the photon is 12119127

a) Infinite b) Zero

c) Very small d) 1.67 ´ 10^-27 Kg

63. The SI unit of Stefen’s constant is: 12119128

a) Wm^-2K⁴ b) Wm^-2K^-4

c) Wm^-4K⁴ d) Wm^-4K^-4

64. An electron is accelerated through a p.d. of 100 V. Its kinetic energy will be: 12119129

a) 100 J b) 100 ergs

c) 100 eV d) 100 MeV

65. If one photon is obtained in annihilation of matter then which of the following conservation law does not hold: 12119130

a) Energy

b) Momentum

c) Charge

d) All these law would not hold

66. In photo electric effect the intensity of light is made twice than initial value. The maximum K.E. of photo electron will be:

12119131

a) Same b) Double

c) Four times d) Half

67. In order to increase the stopping potential of ejected photoelectrons, there should be an increase in: 12119132

a) Intensity of radiation

b) Wavelength of radiation

c) Frequency of radiation

d) Both wavelength and intensity of radiation

68. Which of the following phenomena confirms the wave nature of electrons in the Davisson Germer experiment? 12119133

a) Refraction of electrons

b) Transmission of electrons

c) Diffraction of electrons

d) Dispersion of electron

69. Of the following, the one which has the largest de-Broglie wavelength for the same speed is: 12119134

a) Electron b) Proton

c) a-particle d) Oxygen atom

SHORT ANSWERS

Q.1 What are the results/consequences of Einstein’s special theory of relativity?

12119135

Q.2 The length of a spacecraft might vanishes if it moves with the speed of light. Explain? 12119136

Q.3 An electron of rest mass m_o = 9.1 ´ 10^-31kg is made to move with the sped of
v = 0.999c. Find the increased mass? 12119137

Q.4 Let a ball of mass m = 1Kg is made to move with the speed of light then find the energy associated to this mass? 12119138

Q.5 What is a black body? 12119139

Q.6 What is Stefan Boltzmann’s Law?

12119140

Q.7 Briefly comment on the Max Planck’s explanation of the radiation emitted by a black body? 12119141

Q.8 Write some factors upon which photoelectric effect depends? 12119142

Q.9 Light of wavelength 50 ´ 10^-8 m is incident on a metallic surface. What is the energy of incident photons? 12119143

Q.10 The cut off voltage for a certain metal is 100 Volts. Find the maximum K.E of electron? 12119144

Q.11 Write some important uses of photocells? 12119145

2. Q.12 State Compton effect. 12119146

Q.13 What is the Compton shift in the wavelength of a photon scattered by an electron at an angle 180°? 12119147

Q.14 What amount of energy is needed to carry out phenomena of pair production? 12119148

Q.15 What was the outcome of phenomena of pair production? 12119149

Q.16 What is De-Broglie hypothesis?

12119150

Q.17 Write the De-Broglie wavelength associated to an atomic particle. 12119151

Q.18 Name some particles, which may show wave nature as was proposed by De-Broglie. 12119152

Q.19 Define Annihilation of matter.

12119153

Q.20 State Heisenberg uncertainty principle. 12119154

Unit	ATOMIC SPECTRA
20

MULTIPLE CHOICE QUESTIONS

1. The spectra of a certain excited atom by using was studied 12120036

a) Mass spectrograph

b) Oscilloscope

c) Spectrometer

d) Interferometer

2. The spectrum of visible sunlight ranges from 12120037

a) 400nm to 700nm

b) 600nm to 900nm

c) 656nm to 434nm

d) All of the above

3. The line spectrum can be obtained by

a) Hydrogen b) Water 12120038

c) Carbon d) None of these

4. The Paschen series include energy radiations in the 12120039

a) Visible region

b) Infrared region

c) Ultra violet region

d) All of these

5. For a human eye, the sunlight forms a

a) Line spectrum 12120040

b) Continuous spectrum

c) Emission spectrum

d) None of the above

6. Bohr assumed that electrons move around the nucleus in nearly 12120041

a) Straight path

b) Circular orbits

c) Elliptical orbits

d) None of the above

7. According to Bohr, the energy of revolving electron in one of its allowed orbit appears in the form of 12120042

a) K.E. only

b) P.E. only

c) Both K.E. and P.E.

d) All of the above

8. The quantized radius of 1^st Bohr orbit of a hydrogen atom is: 12120043

a) 0.53m b) 0.053nm

c) 0.53 ´ 10^-10nm d) 1m

9. Electro magnetic radiation having wavelength longer than the red light is known as: 12120044

a) Infrared radiation

b) Ultraviolet radiation

c) Microwaves

d) Gamma rays

10. X-rays have frequency 12120045

a) Higher than UV radiations

b) Lower than UV radiations

c) Equal to infrared radiations

d) Less than radio waves

11. Find the wavelength of the waves of a radio station which is transmitting at 100 ´ 10⁶ Hz. 12120046

a) 3m b) 300m

c) 3 ´ 10⁸m d) 3 ´ 10⁴m

12. The energy required to remove an electron from the atom is called: 12120047

a) Critical energy

b) Excitation energy

c) Ionization energy

d) All of the above

13. X-rays can 12120048

a) Damage the living tissues

b) Affect photographic plate

c) Be used in crystallography

d) All of the above

14. X-rays can 12120049

a) Produce photoelectric effect

b) Be used as scanners

c) Treat cancer d) All of the above

15. The ionization energy for hydrogen is

12120050

a) 1.51 eV b) 3.40 evV

c) 13.6 eV d) 0.053 eV

16. The first excitation energy of hydrogen atom is 12120051

a) -1.51 eV b) 3.40 eV

c) 10.2 eV d) 0.53 eV

17. Laser means 12120052

a) Light amplification by slow energy radiations

b) Light amplification by simple energy radiations

c) Light amplification by stimulated emission of radiations

d) None of the above

18. Laser can be made by creating 12120053

a) Population inversion

b) Meta stable state

c) Assembly

d) All of the above

19. According to de-Broglie, the electrons in the Bohr orbits may appear as 12120054

a) Standing waves b) Particle

c) Photon d) ion

20. According to de-Broglie, standing waves associated with particles are also called

12120055

a) Particle waves

b) Heat waves

c) Infrared radiations

d) Ultraviolet radiations

21. The size (diameter) of an atom is of the order of 12120056

a) 10^-14m b) 10^-10m

c) 10^-16m d) 10^-15m

22. The experimental value of Rydberg’s constant is 12120057

a) 1.097 ´ 10^-7 m^-1

b) 1.097 ´ 10⁷ cm^-1

c) 1.097 ´ 10⁷ m^-1

d) 109.7 ´ 10^-9 m^-1

23. The radius of the nth Bohr’s orbit for H-atom is 12120058

a) , b)

c) d)

24. Total energy of an electron in an orbit around the nucleus is 12120059

a) Positive b) Negative

c) Zero d) None of these

25. The electric force on an electron in an orbit around the nucleus is 12120060

a) Centrifugal Force b) Drag Force

c) Centripetal Force d) All these

26. Hydrogen atom is in its ground (normal) state then the electron is 12120061

a) Within the nucleus

b) In its highest energy level

c) In its lowest energy level

d) All of these

27. According to Bohr’s theory, the outer orbits have greater energy than the inner orbits 12120062

a) Correct

b) Incorrect

c) All the orbits have equal energy

d) None of these

28. In Bohr atomic model, the electron does not fall into the nucleus because 12120063

a) The quantum rules do not allow it

b) The electrostatic attraction is

balanced by mechanical force

c) The electron is not a particle

d) None of the above

29. An electron in an atom will absorb energy only when 12120064

a) It jumps from an outer to an inner orbit

b) It jumps from an inner to an outer orbit

c) it does not jump

d) All of these

30. If an electron in an atom jumps down from outer to inner orbit, it will 12120065

a) Emit energy

b) Absorb energy

c) Neither emit nor absorb energy

d) None of these

31. If an atom exist in the excited state n = 4,
the maximum number of transitions will be 12120066

a) One b) Three

c) Five d) Six

32. Lightest isotope of Hydrogen is also called 12120067

a) Deuterium b) Tritium

c) Protium d) All of these

33. Which one of the following radiations travel at the velocity of light 12120068

a) Radio waves

b) Microwaves

c) Ultra violet waves

d) All

34. Bracket series is obtained when electronic transitions terminate at the 12120069

a) 1^st orbit b) 2^nd orbit

c) 3^rd orbit d) 4^th orbit

35. In the above question, series limit corresponds to 12120070

a) n = 0 b) n = ¥

c) n = 5 d) n = 2

36. Which one of the following series lies in the ultra violet region? 12120071

a) Lyman series b) Pfund series

c) Balmer series d) Bracket series

37. In Bohr’s atom model, the lowest orbit corresponds to 12120072

a) Maximum energy

b) The minimum energy

c) Zero energy

d) Infinite energy

38. The numerical value of ground state energy is maximum for the 12120073

a) 1^st orbit b) 2^nd orbit

c) 3^rd orbit d) 4^th orbit

39. The electrical P.E. of an electron in an orbit around the nucleus is 12120074

a) b)

c) d)

40. The energy of an electron in the 4^th orbit in a H-atom is 12120075

a) -13.60 eV b) -3.40 eV

c) -0.85 eV d) -1.5 eV

41. Balmer series is obtained when all the transitions of electron terminate at 12120076

a) 4^th orbit b) 3^rd orbit

c) 5^th orbit d) 2^nd orbit

42. Which one of the following transitions emits hard photon? 12120077

a) From 4^th to 3^rd orbit

b) From 4^th to 2^nd orbit

c) From 5^th to 2^nd orbit

d) From 5^th to 1^st orbit

43. The numerical value of ground state energy of an electron in an orbit is the measure of 12120078

a) Excitation energy

b) Ionization energy

c) Excitation potential

d) None of these

44. If the ionization energy of hydrogen atom is 13.6 eV, its ionization potential will be:

12120079

a) 13.6 V b) 136.0V

c) 3.4 V d) None of these

45. The excitation energy of an atom to the state n = ¥ is equal to 12120080

a) Potential energy b) Kinetic energy

c) Ionization energy d) None of these

46. The name electron was suggested by

12120081

a) Rutherford b) Chadwick

c) J – J Thomson d) Stoney

47. The de-Broglie wavelength of an electron moving at a speed of 0.01c is 12120082

a) 2.420 nm b) 24.200 nm

c) 0.242 nm d) None of these

48. An excited atom with radius 4.77 will be in the excited state 12120083

a) n = 2 b) n = 1

c) n = 3 d) None of these

Reason: As from the relation r_n = 0.53 x 10^-10n² we get 4.77 x 10^-10 = 0.53 x 10^-10 n²

or n² = = 9 or n = 3

49. The SI unit of Rydberg’s constant is

a) ms^-1 b) m^-112120084

c) m^-2 d) m-sec

50. Total energy of the electron in the state
n = ¥ of H-atom is 12120085

a) Zero b) Infinite

c) 13.6 eV d) 3.4 eV

51. The 2^nd excitation energy of H-atom will be 12120086

a) 12.09 eV b) 3.4 eV

c) 1.70 eV d) None of these

52. X-rays was discovered by 12120087

a) Becqueral b) Merri Curie

c) Roentgen d) Laue

53. X-rays are similar in nature to 12120088

a) Cathode rays b) Positive rays

c) Alpha rays d) g-rays

54. Hydrogen atom does not emit X-rays because 12120089

a) Its energy levels are too close to each

other.

b) Its energy levels are too far apart

c) It is too small in size

d) It has a single electron

55. X-rays absorption will be maximum for sheets of 12120090

a) Silver b) Copper

c) Lead d) Paper

56. When objects placed in a room are exposed to X-rays they become 12120091

a) Violet b) Blue

c) Invisible d) None of these

57. In radio therapy X-rays are used to 12120092

a) Treat cancer

b) Detect bone fracture

c) Both (a) and (b)

d) Detect fault in electronic circuits

58. The penetrating power of X-rays increases with 12120093

a) Increase in their velocity

b) Decrease in their velocity

c) Increase in their intensity

d) Decrease in their intensity

59. Which one of the following is the innermost shell? 12120094

a) M-shell b) K-shell

c) L-shell d) N-shell

60. X-rays spectra are 12120095

a) Purely discrete in nature

b) Purely continuous in nature

c) Both discrete and continuous nature

d) None of these

61. Tick the Correct statement 12120096

a) X-rays can damage the living tissues

b) X-rays can cause ionization of atoms

c) X-rays can cause photoelectric effect

d) All of above

62. Production of X-rays can be regarded as the inverse of 12120097

a) Compton effect

b) Pair production

c) Photoelectric effect

d) Annihilation of matter

63. Holograms are formed by: 12120098

a) Ordinary light b) X-rays

c) Laser d) Gamma rays

64. A laser produces 12120099

a) An incoherent beam of light

b) A coherent beam of light

c) An intense directional and coherent beam of light

d) An intense directional coherent and monochromatic beam of light

65. Normally the excited atoms return to their ground (normal) state in 12120100

a) 10^-5 sec b) 10^-13 sec

c) 10^-10 sec d) 10^-8 sec

66. The Meta stable states of atoms represent

12120101

a) Ground or normal states of atoms

b) De-excited states of atoms

c) Excited states of atoms of long

duration

d) None of the above

67. Lifetime of Meta stable state is 12120102

a) 10^-8 sec or more

b) 10^-5 sec or more

c) 10^-3 sec or more

d) 10^-10 sec or more

68. Operation of a laser depends upon 12120103

a) The existence of atoms in ground state

b) The existence of atoms in excited state

c) The existence of atoms in Meta stable state

d) All the above

69. If the electron in a hydrogen atom jumps from the third orbit to second orbit the emitted radiation has wavelength: 12120104

a) 5/36R b) 36/5 R

c) 6/5 R d) 5 R/6

70. To find the longest wavelength radiation in Balmer series, the value of n used is: 12120105

a) 2 b) 3

c) 4 d) ¥

71. The ratio of the longest and shortest wavelengths of the Lyman series is approximately: 12120106

a) 4/3 b) 9/4

c) 9/5 d) 16/7

72. Bound state energy is always: 12120107

a) Positive b) Zero

c) Negative d) Infinity

73. The Balmer series is found in the spectrum of: 12120108

a) Hydrogen b) Oxygen

c) Nitrogen d) All of these

74. The ratio of life time of meta stable excited state to the life time of normal excited sate is: 12120109

a) 10³ : 1 b) 10^-3 : 1

c) 10⁵ : 1 d) 10^-5 : 1

SHORT QUESTIONS

Q.1 What is spectroscopy? 12120110

Q.2 Name the types of spectra. 12120111

Q.3 List the possible series found in the spectrum of hydrogen atom. 12120112

Q.4 What happens when an electron jumps from higher orbit to some lower orbit? 12120113

Q.5 State any two postulates of Bohr atomic theory. 12120114

Q.6 What is the value of radius of first Bohr orbit? 12120115

Q.7 Define excitation energy. What is ionization energy of H-atom? 12120116

Q.8 Determine the total spectral lines for an excited electron making transition from n = 5 to p = 1 states? 12120117

Q.9 What is the total energy of an electron in ground state of H atom? 12120118

Q.10 How the frequency of X-rays can be found? 12120119

Q.11 Write any three properties of X-rays.

12120120

Q.12 What is a CAT – Scanner? 12120121

Q.13 How uncertainly principle can tell that an electron always lies outside the nucleus? 12120122

Q.14 Differentiate between the terms, normal population and population inversion. 12120123

Q.15 Differentiate between the terms (induced absorption) and spontaneous mission. 12120124

Q.16 What is Meta stable state? 12120125

Q.17 What is the residing time of electrons in the excited state E₁? 12120126

Q.18 What is stimulated emission?

12120127

Q.19 Name the type of lasers. 12120128

1. Q.20 Write any four uses of the laser.

Unit	NUCLEAR PHYSICS
21

MULTIPLE CHOICE QUESTIONS

1. Isotopes of the same element have:

a) Same chemical properties 12121063

b) different chemical properties

c) Same physical properties

d) All of these

2. Mass spectrograph is used to determine the:

a) Number of protons 12121064

b) Number of electrons

c) Isotopes of an element

d) Magnitude of Coulomb’s force present between the nucleons

3. The binding energy can be calculated by:

12121065

a) E=mc² b) E=mgh

c) E=1/2mv² d) E = hf

4. The “binding energy per Nucleon “can be obtained: 12121066

a) Counting the number of electrons

b) Dividing it by number of electrons

c) By multiplying it with number of electrons

d) Dividing the binding energy with the total number of nucleons

5. Disintegration of nucleus obeys the law of conservation of 12121067

a) Charge only

b) Mass only

c) Both mass & charge

d) None of these

6. The spontaneous emission of a, b and g-radiations from certain element is called:

a) Black body radiations 12121068

b) Heat radiations

c) Radio-activity

d) All of the above

7. The half of life of radioactive element depends upon the 12121069

a) Temperature

b) Atmospheric pressure

c) Number of nucleons

d) All of the above

8. The unit of “One Curie” 12121070

a) 693 ´ 10¹⁰ dis/sec

b) 6.93 ´ 10¹⁰ dis/sec

c) 3.70 ´ 10²⁰ dis/sec

d) 3.70 ´ 10¹⁰ dis/sec

9. The SI unit of activity is 12121071

a) Becquerel (Bq) b) Rad

c) Grey d) Sievert

10. All the radio active element have the

a) Different half lives 12121072

b) Same half lives

c) Zero half life

d) Infinite half lives

11. The nuclear fission reaction is the example of an 12121073

a) Exothermic reaction

b) Endothermic reaction

c) Sometimes exothermic and

sometimes endothermic

d) None of the above

12. The minimum mass of fissionable material for self-sustaining chain reaction is 12121074

a) The nuclear mass

b) The critical mass

c) The atomic mass

d) All of these

13. A place where controlled fission chain reaction is carried is called 12121075

a) A black hole

b)Atomic Bomb

c) Mass spectrograph

d) A reactor

14. Identify the true statement about the nuclear reactor 12121076

a) Cadmium or boron is used as a

neutron absorber

b) Graphite is usually used as moderator

c) Uranium rods are usually 2cm in diameter and 1m in length

d) All of the above

15. The fast reactor utilizes 12121077

a) b)

c) d)

16. The working principle of fast reactor is convert into: 12121078

a) b)

c) d) All of the above

17. Hydrogen bomb is an example of

a) Fission reaction 12121079

b) Fusion reaction

c) Chemical reaction

d) Biological reaction

18. Fission reactor can be run from 12121080

a) Water as fuel

b) Uranium as fuel

c) Sodium as fuel

d) Petrol as fuel

19. b-particle is regarded as fast moving

a) Proton b) Electron 12121081

c) Neutron d) Boson

20. g-rays are regarded as: 12121082

a) High energy photons

b) Highly penetrating rays

c) Electromagnetic radiations

d) All of the above

21. g-rays has penetrating power 12121083

a) Equal to a-rays and b-rays

b) Less then α-rays and b-rays

c) Greater than that of a and b-rays

d) None of the above

22. Ionizing power of g-rays is 12121084

a) Equal to that of a-rays

b) Equal to that of b-rays

c) Greater than that of a and b-rays

d) None of the above

23. Nuclear radiations can be detected by the use of: 12121085

a) Solid state detector

b) Geiger counter

c) Wilson cloud chamber

d) All of the above

24. Working of most of radiations detector is based upon the: 12121086

a) counting of number of particles

b) penetrating power of radiation

c) Fluorescence caused by radiation

d) Ionization caused by radiations

25. The minimum safe dose limit for persons working in a nuclear reactor is: 12121087

a) 1 rem b) 3 rem

c) 4 rem d) 5 rem

26. For the treatment of skin disease 12121088

a) g-radiations are used

b) b-radiations are used

c) a-radiations are used

d) None of the above

27. Which of the following is a better shield against g-rays 12121089

a) Heavy water b) Ordinary water

c) Aluminum d) Lead

28. g-rays can be used to detect 12121090

a) Deep cancerous tumors

b) Cracks or faults in engine and other machinery

c) Cavities in metal plates

d) All of the above

29. The process in which the age of old things e.g. fossils can be found, is called:

12121091

a) Radio graphy b) Radio active dating

c) Polymerisation d) None of these

30. The number of fundamental forces present in nature are: 12121092

a) 1 b) 2

c) 3 d) 4

31. Dr. Abdus Salam of Pakistan was one of contributor to the unification of 12121093

a) Electromegnatic force and gravitational force

b) Electromagnetic force and weak nuclear force

c) Gravitational force and weak nuclear force

d) Weak nuclear force and the strong nuclear force

32. The weakest force of all the forces

12121094

a) Electro weak force

b) Strong nuclear force

c) Gravitational force

d) None of these

33. The building blocks of protons and neutrons are called: 12121095

a) Ions b) Neutrino

c) Electron d) Quarks

34. Quarks are of: 12121096

a) 2 types b) 4 types

c) 6 types d) Infinite

35. Quarks carry 12121097

a) No charge no mass

b) No charge no spin

c) Charge as well as spin

d) All of the above

36. Identify the true statement among the following 12121098

a) Hadrons are made up of quarks

b) For every quark there is an anti quark

c) Brayons and mesons are the two major types of hadrons composed of quarks

d) All of the above

37. Minimum of three quarks are necessary to form a 12121099

a) Proton b) Neutorn

c) Proton and neutron d) Photon

38. The lightest particle of matter which can physically exists is called 12121100

a) Photon b) Neutron

c) Electron d) Proton

39. Radio activity was discovered by 12121101

a) Pierre Curie b) Becquerel

c) Thomson d) Rontgen

40. a, b and g-rays are emitted from a radioactive substance 12121102

a) When it is heated

b) When it interacts with another particle

c) Spontaneously

d) None of the above

41. The half life of radioactive element is

12121103

a) b)

c) d)

42. Fission reaction can be induced in with 12121104

a) Slow neutrons

b) Fast neutrons

c) Thermal neutrons with energy between 1MeV and 1.2 MeV

d) None of the above

43. Release of energy in fission reaction is due to conversion of 12121105

a) Gravitational forces

b) Electrostatic forces

c) Mass

d) Charge

44. Which one of the following cannot be used as moderator? 12121106

a) Graphite b) Heavy water

c) Lead d) None of these

45. The atomic bomb is an example of:

12121107

a) Controlled nuclear fission

b) Controlled nuclear fusion

c) Uncontrolled nuclear fission

d) Uncontrolled nuclear fusion

46. When four Hydrogen atoms combine to form a Helium atom, this is called

a) Fission reaction 12121108

b) Fusion or thermo-nuclear reaction

c) Nuclear transmutation

d) None of the above

47. During fusion of Hydrogen into Helium

a) Energy is absorbed 12121109

b) Energy is released

c) Mass is increased due to energy absorption

d) Mass is reduced due to energy released

48. The amount of energy required to break the nucleus is called its: 12121110

a) Kinetic energy b) Potential energy

c) Binding energy d) Nuclear energy

49. Mass defect per nucleon is called

a) Binding energy of nucleus 12121111

b) Packing fraction of nucleus

c) Average energy of nucleus

d) Excitation energy of nucleus

50. An a-particle is the nucleus of 12121112

a) Deuterium b) Helium

c) Tritium d) Protium

51. The binding energy of helium is, 12121113

a) 2.82 MeV b) 282.0 MeV

c) 28.2 MeV d) 0.282 MeV

52. The binding energy of deutron is 12121114

a) 2.224 MeV b) 22.24 MeV

c) 222.4 MeV d) None of these

53. Nuclear forces exist between 12121115

a) Proton – proton

b) Proton – neutron

c) Neutron – neutron

d) All of the above

54. During fission process, the average number of neutrons emitted are 12121116

a) 2 b) 3

c) 2.5 d) 1

55. The half life of radium is 1600 years. The fraction of radium sample in the universe survive after 6400 years (4 half lives) is:

a) b) 12121117

c) d)

56. Half life of a given sample of radium is 22 years. The sample will reduce to 25% of its original value after 12121118

a) 11 years b) 22 years

c) 44 years d) 88 years

57. Out of the following particles the one whose anti particle does not exist is

12121119

a) Electron b) Proton

c) Photon d) Messon

58. Fusion of two lighter nuclei can take place 12121120

a) Without collision

b) Through collision

c) Either with collision or without collision

d) None of these

59. Chemical properties of an atom are determined by its: 12121121

a) Mass number b) Atomic number

c) Binding energy d) None of these

60. The source of energy in the sun and the star is namely due to 12121122

a) Fission reaction

b) Fusion reaction

c) Chemical reaction

d) None of these

61. For chain reaction to build up the size of the fissionable target should be 12121123

a) Greater than the critical size

b) Less than the critical size

c) Equal to the critical size

d) None of above

62. Fission chain reaction in a nuclear reactor can be controlled by introducing

12121124

a) Iron rods b) Graphite rods

c) Cadmium rods d) Platinum rods

63. Energy liberated when one atom of U-235 undergoes fission is 12121125

a) 200 MeV b) 40 MeV

c) 30 MeV d) 20 MeV

64. Splitting up of a heavy nucleus into two lighter nuclei is called 12121126

a) Fusion reaction

b) Fission reaction

c) Exothermic reaction

d) None of these

65. Tick the correct statement, natural uranium contains: 12121127

a) 99.3% of and 0.7% of

b) is fissionable with slow neutron

c) Fission of with slow neutrons was discovered by Hahn and Strassman

d) All of above

66. The example of fusion reaction is 12121128

a) The formation of water from oxygen and hydrogen

b) The formation of barium and krypton from uranium

c) The formation of helium from hydrogen

d) None of these

67. When an electron combines with a positron, the number of photons emitted will be? 12121129

a) One b) Two

c) Three d) Four

68. An a particle ionizes a molecule or atom:

a) Through direct collision 12121130

b) Through electrostatic attraction

c) The electrostatic repulsion

d) None of these

69. Capture of a neutron by a nucleus results in the formation of: 12121131

a) Duetron b) Tritron

c) Radio istope d) Radio isobar

70. Cloud chamber was invented by C.T.R. Wilson in 12121132

a) 1913 b) 1906

c) 1911 d) 1909

71. In the cloud chamber we use super saturation condition 12121133

a) Through isothermal compression

b) Through adiabatic expansion

c) Through isothermal expansion

d) Through adiabatic compression

72. A cloud chamber uses: 12121134

a) Vapours

b) Super saturated vapours

c) Super heated liquid

d) None of these

73. In a cloud chamber the ionizing particle can be detected by 12121135

a) Taking photograph of its path

b) The sound it produces

c) The amount of ionization it produces

d) both (a) and (c)

74. Geiger-Muller counter contains mixture of 12121136

a) Argon and Alcohol

b) Bromine mixed with Neon

c) Different gases at different pressure according to the radiation to be examined

d) None of the above

75. In Geiger counter a thin metallic wire passing through the centre of the metal tube is 12121137

a) Earthed

b) Connected to the tube

c) Insulated from the tube

d) None of these

76. In Geiger counter 12121138

a) The metal tube acts as the cathode and wire acts as the anode

b) The metal tube acts as the anode and wire acts as the cathode

c) Both metal tube and wire acts as cathode or anode

d) None of these

77. The process of making the gas non-conducting immediately after the passage of ionization particles through the tube is called 12121139

a) Excitation of discharge

b) De-excitation of discharge

c) Quenching of discharge

d) None of above

78. Geiger counter is suitable 12121140

a) For fast counting

b) For extremely fast counting

c) For slow counting

d) None of these

79. Geiger counter is widely used in 12121141

a) Laser experiments

b) Radioactivity experiments

c) Optical spectra

d) All of these

80. Geiger counter can be used to determine penetration power of 12121142

a) a - particles & b - particles

b) b - particles & g - particles

c) a - particles & g - particles

d) a - b and g - particles

81. Specially designed solid state detector can be used to detect 12121143

a) a - particles only

b) b - particles only

c) g - particles only

d) None of the above

82. g - rays differ from X-rays in respect of their 12121144

a) Origin b) Velocity

c) Spin momentum d) Charge

83. The g-rays photon is stronger than

12121145

a) Ultra-violet ray photon

b) X-ray photon

c) Micro-wave photon

d) All of the above

84. Depletion of ozone layer is attributed to the release of 12121146

a) CFC (chloro flouro carbons)

b) Carbon dioxide

c) Heat energy

d) None of these

85. The tracer techniques are being used to:

12121147

a) Diagnose and care unknown diseases

b) Get full information on the series of chemical reactions

c) Detect exact position of underground pipes and leakage in them if any

d) All the above

86. The most useful tracer is 12121148

a) Strontium – 90 b) I – 131

c) C – 12 d) C – 14

87. The half life of carbon – 14 is 12121149

a) 5900 years b) 5870 years

c) 5730 years d) 6300 years

88. The sum of protons and neutrons is called:

12121150

a) Charge number b) Mass number

c) Atomic number d) Quantum number

89. Which of the following conservation law hold in nuclear transmutation: 12121151

a) Mass b) Energy

c) Momentum d) All these laws

90. In order to separate isotopes of an element which method is used: 12121152

a) Chemical b) Physical

c) Both a and b d) None of these

91. Which of the following basic forces is able to provide an attraction between two neutrons: 12121153

a) Electrostatic and nuclear

b) Electrostatic and gravitational

c) Gravitational and strong nuclear

d) Only nuclear force

92. A radioactive substance has a half life of 4 months. Three fourth of the substance will decay in: 12121154

a) 6 months

b) 8 months

c) 12 months

d) 16 months

93. The half life of a radioactive element is 1500 years the fraction of sample that would survive after 6000 years is: 12121155

a) b)

c) d)

94. Meson is made from: 12121156

a) A pair of quarks

b) A pair of quark and antiquark

c) A pair of antiquarks

d) Three quarks

95. The energy of photon for pair production is: 12121157

a) 0.51 MeV b) 1.02 MeV

c) 0.31 MeV d) 0.25 MeV

96. Mass spectrongraph is used to: 12121158

a) Separate isotopes

b) Find neutrons

c) Separate isotones

d) Both (a) and (b)

97. By increasing the mass number, which of the followings does not change? 12121159

a) Mass b) Density

c) Volume d) B.E.

98. Nuclear weak force is experienced during: 12121160

a) a decay b) b Decay

c) g decay d) All of these

SHORT QUESTIONS

Q.1 Differentiate between atomic number and mass number. 12121161

Q.2 How isotopes of an element can differs from the other isotope of the same element?

12121162

Q.3 What is the mass defect? How it appeared? 12121163

Q.4 How the nucleus of differs from a nucleus of ? 12121164

Q.5 Who discovered natural radioactivity? 12121165

Q.6 What happens to the nucleus, which emits an a-particle? 12121166

Q.7 What is g-ray? 12121167

Q.8 What is decay constant? 12121168

Q.9 What is the main interaction of any radiation with the matter? 12121169

Q.10 Write any two properties of a – particles. 12121170

Q.11 Write any two properties of b-particles. 12121171

Q.12 In what ways g-rays may interact with the matter? 12121172

Q.13 Name some radiation detectors.

12121173

Q.14 Write some properties of a solid-state detector. 12121174

Q.15 Define nuclear fusion with the help of a suitable example. 12121175

Q.16 Name the basic parts of a nuclear reactor. 12121176

Q.17 What the word PWR stands for?

12121177

Q.18 Which place is the most safest place to dump a nuclear waste? 12121178

Q.19 What is P – P reaction? 12121179

Q.20 Classify the biological effects of radiations. 12121180

Q.21 Define one Becquerel. 12121181

Q.22 How “Bq” and Curie “Ci” are related to each other? 12121182

Q.23 What is absorbed dose? 12121183

Q.24 What the words RBE , SV and rem means to you? 12121184

Q.25 Write at least four areas where radioisotopes are most widely used? 12121185

Q.26 Mention any one use of each of the following istopes. Na – 24, Cobalt – 60, Iodine – 131 and Strontium – 90? 12121186

Q.27 Name the forces, which are unified so far. 12121187

Q.28 Differentiate between Hadrons & Leptons. 12121188

Causative

12th Physics Objectives + short questions

a. SHORT ANSWERS

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