Chapter 10: Heat

1

Which of the following expands on heating?

A Only solids B Only liquids C Only gases D Solids, liquids, and gases

2

Which of the following is the best example of thermal expansion in daily life?

A A metal lid on a glass jar becomes easier to open after running it under hot water. B A balloon bursts when taken to a higher altitude. C A mirror reflects light in a dark room. D A magnet attracts iron nails.

3

A bimetallic strip bends when heated because:

A Both metals expand equally B The two metals expand unequally C One metal contracts D It is magnetic

4

In an automobile engine, the radiator is used to:

A Increase engine temperature B Cool the engine C Lubricate the engine D Filter air

5

Which of these best explains why automobile engines have cooling systems?

A To prevent the engine from overheating due to heat produced B To increase the speed of the car C To reduce fuel consumption D To make the engine quieter

6

Which of the following is a daily life example of thermal expansion?

A A metal lid stuck on a glass jar loosened by running hot water B Ice melting in a glass C Water boiling in a kettle D Clothes drying in the sun

7

Which of the following statements correctly differentiates between heat and temperature?

A Heat is measured in Kelvin, while temperature is measured in Joule. B Heat is the total energy of particles, while temperature is the average kinetic energy of particles. C Heat and temperature are the same physical quantity. D Heat is a scalar, while temperature is a vector.

8

The boiling point of pure water at normal atmospheric pressure is:

A 90 °C B 100 °C C 110 °C D 120 °C

9

Which of the following is a bad conductor of heat?

A Iron B Aluminum C Rubber D Copper

10

Which of the following expands the most for the same rise in temperature?

A Solids B Liquids C Gases D All expand equally

11

Gaps are left between railway tracks because:

A To save material B To allow for expansion in summer C To reduce friction D To make the track stronger

12

Convection currents in liquids and gases are due to

A difference in density caused by temperature difference B vibration of particles in fixed positions C electromagnetic waves D direct contact between particles

13

Thermal expansion of a solid occurs because

A the particles gain mass B the average distance between particles increases C the particles lose energy D the number of particles decreases

14

The melting point of pure ice at standard atmospheric pressure is:

A 0 °C B 32 °C C 100 °C D –10 °C

15

Which of the following is the best explanation for why railway tracks have small gaps between sections?

A To allow the tracks to expand in hot weather without bending B To allow the tracks to contract in cold weather without breaking C To reduce friction between train wheels and tracks D To allow water to drain off the tracks

16

Why do electronics need cooling fans?

A To prevent overheating due to heat produced during operation B To increase the speed of the device C To make them look attractive D To reduce electricity consumption

17

Which of the following is a unit of heat?

A Calorie B Kelvin C Ampere D Volt

18

The melting point of ice at normal atmospheric pressure is

A 0°C B 4°C C 100°C D -10°C

19

The boiling point of water at normal atmospheric pressure is:

A 0°C B 100°C C 212°C D 273°C

20

During melting, the temperature of a pure substance:

A Increases continuously B Decreases continuously C Remains constant D Fluctuates randomly

21

What is the melting point of pure ice at normal atmospheric pressure?

A 0°C B 100°C C 273 K D Both A and C

22

Heat transfer by conduction mainly takes place in:

A Solids B Liquids C Gases D Vacuum

23

In which of the following does convection occur?

A Solids B Liquids and gases C Vacuum D Metals

24

Which of the following statements correctly describes the difference between heat and temperature?

A Heat is a measure of the average kinetic energy of particles, while temperature is the total energy transferred. B Heat is the total thermal energy of a body, while temperature is the average kinetic energy of its particles. C Heat and temperature are the same physical quantity expressed in different units. D Heat is measured in degrees Celsius, while temperature is measured in joules.

25

Why do automobile engines have gaps between metal parts?

A To allow for thermal expansion when the engine gets hot B To reduce the weight of the engine C To allow air to escape from the engine D To make the engine look better