Name: ______________________
Subject:
Physics (Ch # 8,9) Class:
IX Total Marks: 12
(1) Rooms are heated using gas heaters by:
(a) Conduction only (b) Convection and radiation (c) Radiation only (d) Convection
only
(2) Metals are good conductor of heat due to the
(a) free electrons (b) big size molecules (c) small size molecules (d) rapid vibrations of their atoms
(3) In gases, heat is mainly
transferred by:
(a) molecular collision (b) conduction (c) convection (d) radiation
(4) Convection of heat is the
process of heat transfer due to _________________ of Molecules.
(a) random motion (b) downward movement (c) upward movement (d) free movement
(5) Which of the following surface is a good radiator of heat?
(a)
shining silvered (b) dull black (c)
white black (d) shining
colored
(6) The process in which heat is
transferred due to the actual movement of the molecule is called:
(a)
Conduction (b) Radiation (c)
Convection (d) All of these
(7) Heat
transfer in rod depends upon
(a) Length (b)
cross-sectional Area (c) mass (d)
material of rod
(8) The
quantity of heat absorbed by the body depends upon:
(a) Colour of surface (b) Nature of surface (c)
Shape of surface (d) Both a & b
(9) Dull
black surface is the best:
(a) Emitter (b)
Absorber (c)
Reflector (d) None of these
(10) The unit of heat capacity is
(a) Jkg K (b) JK-1 (c) Jkg-1K (d)
J-1kg-1K-1
(11)
Which gas is used in spite of Freon gas in the refrigerator? (Board 2013)
(a) CO2 (b)
H2 (c) NH3 (d) N2
(12)
In Celsius lower reference point is 0oC
while the upper reference point is
(a) 2120C (b) 1800C (c) 1000C (d) 1100C
Subjective Part
Subject: Physics Class: IX Total Marks: 38
2.
Answer any 15 Questions 2 × 15 = 30
i.
Differentiate
between Temperature and Heat.
ii.
what is the internal energy of a body? (Board 2014)
iii.
Write properties
of thermometric materials? Also, define thermometric substances.
iv.
What do
you mean by lower and upper fixed points? (Board 2015
v.
How can we
convert temperature from one scale to another? Write formulas
vi.
Write the
importance of the large specific heat capacity of water.
vii.
Define
fusion point and freezing point.
viii.
Why overhead transmission lines are given a certain amount of Sag?
ix.
Write two applications of thermal expansion in our daily life?
x.
What is
meant by Bimetal Strip? Write its uses.
xi.
Why metals
are good conductors of heat?
xii. How does heat reach us from the sun?
xiii.
On what factors does radiation depend?
xiv.
Write down four uses of conductors and
Non-conductors?
xv.
Suggest a simple activity to show the convection
of heat in gases. given in the book.
xvi.
A container has 2.5 liters
of water at 20oC. How much heat is required to boil the water?
Note: Attempt All questions. (2×4=8)
1. (a ) What are the
applications and consequences of Radiation?
(b) An
electric heater supplies heat at the rate of 1000 joule per second. How much
time is required to raise the temperature of 200 g of water from 20 oC
to 90 oC?
