# MCQ Questions for Class 11 Physics Chapter 11 Thermal Properties of Matter with Answers

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## Thermal Properties of Matter Class 11 MCQs Questions with Answers

Multiple Choice Type Questions

Question 1.
A liquid with coefficient of cubical expansion γ is contained in a vessel having coefficient of linear expansion $$\frac {γ}{7}$$. When heated, what will happen to the level of the liquid in the vessel?
(a) It falls
(b) It rises
(c) Remains unchanged
(d) It may rise or fall depending upon the nature of the container

Answer: (c) Remains unchanged

Question 2.
The temperature determines the direction of net change of:
(a) gross potential energy
(b) intermolecuiar potential energy
(c) gross kinetic energy
(d) intermolecuiar kinetic energy

Answer: (d) intermolecuiar kinetic energy

Question 3.
Thermal equilibrium implies equality of:
(a) energy
(b) internal energy
(c) K.E.
(d) temperature

Question 4.
Two bars of copper having same length but an equal diameter are heated to the same temperature. The change in length will be:
(a) more in thicker bar
(b) more in thinner bar
(c) same for both
(d) determined by the ratio of length and diameter of the bars

Answer: (c) same for both

Question 5.
A metallic ball has a spherical cavity at its centre. If the ball is heated, what happens to the cavity?
(a) Its volume decreases
(b) Its volume increases
(c) Its volume remains unchanged
(d) Its volume may increase or decrease depending upon the nature of the metal

Answer: (b) Its volume increases

Question 6.
Two blocks of ice when pressed together join to form one block. This happens because
(a) melting point rises with pressure
(b) melting point falls with pressure
(c) heat is rejected to outside
(d) heat is absorbed from outside

Answer: (b) melting point falls with pressure

Question 7.
The running of fan makes us comfortable during summer because it:
(a) increases the conductivity of the air
(b) reduces the thermal radiation
(c) cools the air
(d) enhances the rate of evaporation of perspiration

Answer: (d) enhances the rate of evaporation of perspiration

Question 8.
Gas thermometers are more sensitive than liquid thermometers as the gases
(a) have low specific heat
(b) have high specific heat
(c) have large coefficient of expansion
(d) are lighter

Answer: (c) have large coefficient of expansion

Question 9.
An iron ball is heated. The percentage increase will be largest in
(a) density
(b) surface area
(c) diameter
(d) volume

Question 10
What happens when pressure is raised on the surface of water?
(a) Boiling point decreases and melting point increases.
(b) Boiling point increases and melting point decreases.
(c) Both boiling and melting point decreases.
(d) Both boiling and melting point increases.

Answer: (b) Boiling point increases and melting point decreases.

Question 11.
In the pressure cooker, the cooking is faster because the increase of vapour pressure :
(a) increases melting point
(b) increases boiling point
(c) decreases boiling point
(d) decreases melting point

Answer: (b) increases boiling point

Question 12.
Bimetallic strips cannot be used as
(a) thermostat
(b) electricity generator
(c) thermometer
(d) a switch to put on or off an electric circuit

Answer: (b) electricity generator

Question 13.
On which of the following property of the body, the coefficient of thermal expansion depends?
(a) Shape
(b) Size
(c) Temperature
(d) P.E. curve

Answer: (d) P.E. curve

Question 14.
By increasing the temperature of a liquid, its
(a) volume and density increases
(b) volume and density decreases
(c) volume increases and density decreases
(d) volume decreases and density increases

Answer: (c) volume increases and density decreases

Question 15.
When water is heated from 0°C to 10°C, its volume will:
(a) decrease
(b) increase
(c) first decrease then increase
(d) not change

Answer: (c) first decrease then increase

Question 16.
One gram of ice is mixed with lg of steam. After thermal equilibrium, temperature of the mixture is
(a) 0°C
(b) 100°C
(c) 75°C
(d) 50°C

Question 17.
A circular disc is heated. Its M.I. about an axis passing through its centre and perpendicular to its plane
(a) increases
(b) decreases
(c) remains same
(d) first increases and then decreases

Question 18.
A beaker is completely filled with water at 4°C. It will overflow
(a) when heated but not when cooled
(b) when cooled but not when heated
(c) neither when heated nor when cooled
(d) both when cooled or heated

Answer: (d) both when cooled or heated

Question 19.
S.I. unit of heat is
(a) Joule
(b) Calorie
(c) Kilo calorie
(d) None of the above

Question 20.
The density of water at 20°C is 998 kg m-3 and that at 40°C is 992 kg m-3. The coefficient of cubical expansion of water is
(a) 0.2 × 10-40C-1
(b) 0.6 × 10-40C-1
(c) 3.02 × 10-40C-1
(d) 0.4 × 10-40C-1

Answer: (c) 3.02 × 10-40C-1

Question 21.
Alcohol is more volatile than water because the
(a) boiling point of alcohol is > than that of water
(b) boiling point of alcohol is < than that of water
(c) melting point of alcohol is < than that of water (d) melting point of alcohol is > than that of water

Answer: (b) boiling point of alcohol is < than that of water

Question 22.
A liquid boils at a temperature at which the pressure of air on its surface is
(a) less than the vapour pressure
(b) more than the vapour pressure
(c) equal to the vapour pressure
(d) equal to 760 mm of Hg

Answer: (c) equal to the vapour pressure

Question 23.
The top of lake is frozen as the atmospheric temperature is -10°C. The temperature at the bottom of the lake is most likely to be
(a) 0°C
(b) -4°C
(c) 4°C
(d) -10°C

Question 24.
A liquid having coefficient of cubical expansion y is filled in the container having coefficient of linear expansion a. If liquid overflows on heating, then which one is correct?
(a) γ = 2α
(b) γ > 3α
(c) γ < 3α
(d) γ = 2α

Answer: (b) γ > 3α

Question 25.
Heat is
(a) energy in transit
(b) P.E. of molecules
(c) K.E. of molecules
(d) P.E. and K.E. of molecules

Answer: (a) energy in transit

Fill in the blanks

Question 1.
Both thermal and electrical conductivity depends upon the ……………..

Answer: number of free electrons.

Question 2.
Density of water is …………….. at 4°C and volume is …………….. and coefficient of cubical expansion of water is ……………..

Answer: maximum, zero, zero.

Question 3.
Coefficient of cubical expansion of a gas …………….. with the rise in temperature.

Question 4.
Invar has …………….. value of coefficient of linear expansion and hence pendulums made of it are used in clocks to give …………….. time.

Question 5.
When an iron ball is heated, then the percentage increase is largest in ……………..

Question 6.
……………. thermometers are more sensitive than …………….. thermometers.

Question 7.
A thermometer bulb should have …………….. heat capacity.

Question 8.
It is hotter at the same distance over the top of fire than in front of it because ……………..

Answer: we receive heat both due to radiation and convection above the. fire while in front of fire we receive heat only by radiation.

Question 9.
We don’t feel warm without clothes although air is a bad conductor of heat because ……………..

Answer: our body which is comparatively at a higher temperature acts as a source and thus it starts losing heat by convection and radiation.

Question 10.
…………….. have negative temperature coefficient.

Question 11.
…………….. constituting the body causes its hotness.

Answer: K.E. of the molecules.

Question 12.
…………….. is the property of a body that determines whether it is in thermal equilibrium with its surroundings or not.

Question 13.
Solid CO2 called ……………..

Question 14.
…………….. is the process of refreezing.

Question 15.
…………….. is a gas above critical temperature and ………………. is a vapour below the criticial temperature.

Question 16.
The temperature upto which gas can be liquified by applying pressure alone is called ……………..

True/False Type Questions

1. Heat is absorbed by a body but its temperature does not rise. Which of the following statement is True/False about the phenomenon?
(a) Only P.E. of intermolecular force fields increases.
(b) Only K.E. of vibration increases.
(c) No increase in internal energy takes place.
(d) Increase in K.E. is balanced by decrease in P.E.

(a) True
(b) False
(c) False
(d) False

2. Two spheres are made of same material and have same mass. One is solid and another is hollow. When heated to the same temperature, then which one of the following statement is True/ False?
(a) It will be more for solid sphere.
(b) It will be more for hollow sphere.
(c) It will be same for both spheres.

(a) False
(b) False
(c) True

3. Select which one of the following statement is True/ZFalse?
(a) K.E. of molecules constituting the body cause hotness of the body.
(b) Physical changes such as expansion, change of colour or state or electrical properties may take place on heating.
(c) Bodies are not the same temperature in thermal equilibrium.

(a) True
(b) True
(c) False

4. Which one of the following is True/False?
(a) Coefficients of thermal expansion for a given solid are constant.
(b) Temperature coefficient of resistance is more for alloy than for metals.
(c) Temperature coefficient is always positive.

(a) False
(b) False
(c) False

5. Select True/False statements :
(a) Coefficients of expansion differ when lengths are measured in C.G.S. and S.I. system.
(b) A substance may contract on heating.
(c) A glass stopper is taken out easily from the bottle neck on heating the neck.

(a) False
(b) True
(c) True

6. Select True/False statement:
(a) Water and ice have the same specific heat.
(b) Specific heat of sand is less than that of water.
(c) Tea gets cooled on adding sugar in it.

(a) False
(b) True
(c) True

7. Select True/False statements
(a) Specific heat of a gas can be infinity.
(b) Specific heat of a gas can be negative.
(c) Molar specific heat of a solid is a constant quantity.

(a) True
(b) False
(c) True

8. Select True/False statements :
(a) Heat lost is equal to heat gained is the principle of mixture.
(b) Water is used as a coolent as it can absorb large amount of heat.
(c) Water is used as coolent as it has very high specific heat.

(a) True
(b) True
(c) True

9. Select True/False statements
(a) Triple point of water is used as the single reference point for constructing a temperature scale.

10. Select True/False statements
(a) Mercury is a good conductor of heat and attains the temperature of the hot bath quickly.
(b) Mercury has uniform coefficient of expansion over a wide range of temperature.

(a) True
(b) True

Match Type Questions

 Column I Column II (a) A gas can be liquified by applying pressure alone upto (i) dry ice (b) Solid CO2 (ii) due to decrease in its internal energy (c) A gas is cooled on expansion (iii) radian (d) Fastest mode of heat transfer (iv) critical temperature (e) Heat lost = heat gain (v) Principle of Calorimity (f) Water contracts on heating (vi) temperature (g) Conduction mainly takes place in (vii) liquids and gases (h) Convection takes place in (viii) for 0 to 4°C (i) Degree of hotness of the body (ix) heat (j) It is a form of energy (x) solids