Thermal Physics Quizzes: Test Your Understanding of Heat and Temperature

Question 1

Which assumption of the ideal gas model is not valid?

Accepted Answer

Gas particles do not interact with each other.

Answer

Gas particles are point masses with no volume.

Answer

Gas particles are in constant, random motion.

Answer

The average kinetic energy of gas particles is proportional to the absolute temperature.

Question 2

The kinetic theory of gases states that the average kinetic energy of gas molecules is:

Accepted Answer

directly proportional to the temperature of the gas

Answer

directly proportional to the gas pressure

Answer

inversely proportional to the volume of the gas

Answer

constant for all gases at a given temperature

Question 3

Which statement about the kinetic theory of gases is incorrect?

Accepted Answer

Gas particles collide with each other perfectly elastically

Answer

Gas particles are in constant random motion

Answer

The average kinetic energy of gas particles is proportional to the absolute temperature of the gas

Answer

Gas particles have negligible volume compared to the volume of the container they occupy

Question 4

In an isothermal process for an ideal gas, what happens to the product of its pressure and volume?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Becomes zero

Question 5

A gas has a volume of 10.0 dm³ at a pressure of 1.50 atm. If the pressure is reduced to 0.750 atm at constant temperature, what will be the new volume of the gas?

Accepted Answer

5.00 dm³

Answer

10.0 dm³

Answer

15.0 dm³

Answer

20.0 dm³

Question 6

A gas sample is held in a sealed container at constant pressure. The temperature of the gas is increased from 298 K to 313 K. What is the percentage increase in the volume of the gas?

Accepted Answer

5.03%

Answer

5%

Answer

10%

Answer

10.06%

Question 7

During an isothermal process involving an ideal gas, which quantity remains unchanged?

Accepted Answer

Temperature

Answer

Pressure

Answer

Volume

Question 8

When a liquid transforms into a gas, the energy needed to break the intermolecular attraction and separate the molecules is known as:

Accepted Answer

Latent heat of vaporization

Answer

Sensible heat

Answer

Latent heat of fusion

Question 9

In irreversible processes, what happens to the total entropy of the system and its surroundings?

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

Can either increase or decrease, depending on the process

Question 10

Which of the following is NOT a method of thermal energy transfer?

Accepted Answer

Evaporation

Answer

Conduction

Answer

Convection

Answer

Radiation

Question 11

An isothermal process maintains a constant temperature. Which of the following processes is **not** isothermal?

Accepted Answer

Adiabatic expansion of an ideal gas

Answer

Reversible expansion of an ideal gas

Question 12

When solids are heated, what primarily causes them to expand?

Accepted Answer

Increased molecular vibration, leading to greater spacing between molecules.

Answer

Breaking of intermolecular forces between molecules.

Answer

Change in molecular shape, resulting in a larger overall volume.

Question 13

During a phase transition from liquid to gas, energy is absorbed to overcome intermolecular forces and provide kinetic energy for molecules to escape the liquid. What is this energy known as?

Accepted Answer

Latent Heat

Answer

Internal Energy

Answer

Kinetic Energy

Answer

Specific Heat

Question 14

As a solid is heated, its molecules undergo thermal expansion in all directions. Which of the following best explains this phenomenon at the molecular level?

Accepted Answer

Increased thermal energy amplifies the vibration of molecules, increasing the average distance between them.

Answer

Increased thermal energy facilitates the movement of electrons, reducing the attractive forces between molecules.

Answer

Increased thermal energy disrupts bonds between molecules, leading to the formation of longer bonds.

Question 15

Define entropy and explain its significance in determining whether a process is spontaneous.

Accepted Answer

Entropy measures the disorder of a system and increases in spontaneous processes.

Answer

Entropy measures the energy of a system and decreases in spontaneous processes.

Answer

Entropy measures the temperature of a system and increases in spontaneous processes.

Question 16

An enclosed container holds an ideal gas at a constant temperature. If the container's volume is reduced by half, what will happen to the gas pressure?

Accepted Answer

It doubles.

Answer

It halves.

Answer

It stays the same.

Question 17

Define entropy and explain its significance in determining the direction and spontaneity of processes. Discuss how entropy changes in different types of systems.

Accepted Answer

Entropy is a measure of disorder, and processes tend to proceed in the direction of increasing entropy.

Answer

Entropy is a measure of energy, and processes tend to proceed in the direction of decreasing entropy.

Answer

Entropy is a measure of temperature, and processes tend to proceed in the direction of increasing temperature.

Answer

Entropy is a measure of heat, and processes tend to proceed in the direction of increasing heat.

Question 18

Identify the SI unit of latent heat.

Accepted Answer

Joule per kilogram

Answer

Joule

Answer

Kelvin

Answer

Watt per square meter

Question 19

According to the first law of thermodynamics, which process violates the principle of energy conservation?

Accepted Answer

Creation of matter from energy

Answer

Evaporation of water

Answer

Heat transfer between two objects

Answer

Burning of fuel

Question 20

Which of the following is a direct consequence of the second law of thermodynamics?

Accepted Answer

Heat naturally flows from hot to cold objects

Answer

Entropy of an isolated system never increases

Answer

Heat engines can operate with 100% efficiency

Answer

Time can flow backward under certain conditions

Question 21

Which of the following is the SI unit of latent heat?

Accepted Answer

Joules per kilogram

Answer

Joules

Question 22

The first law of thermodynamics states that:

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed

Answer

Entropy always increases in a closed system

Answer

Heat flows from hot to cold objects

Answer

The total amount of work done in a closed system is always zero

Question 23

Which of the following processes involves the transfer of heat from one object to another without direct contact?

Accepted Answer

Radiation

Answer

Conduction

Answer

Convection

Question 24

A heat engine is a device that:

Accepted Answer

Converts heat into mechanical energy

Answer

Converts mechanical energy into heat

Question 25

The efficiency of a heat engine is defined as:

Accepted Answer

The ratio of the work done to the heat input

Answer

The ratio of the heat input to the work done

Question 26

Which of the following is NOT a factor that affects thermal conductivity?

Accepted Answer

Pressure

Answer

Temperature

Answer

Molecular structure

Question 27

Which unit is used to measure thermal energy?

Accepted Answer

Joule

Answer

Celsius

Answer

Kelvin

Answer

Watt

Question 28

Which statement does NOT represent a principle of the second law of thermodynamics?

Accepted Answer

All processes are reversible.

Answer

Heat cannot spontaneously flow from a colder to a hotter object.

Answer

The entropy of an isolated system can only increase or remain constant.

Answer

No work can be extracted from a system operating in a cycle.

Question 29

A heat engine operates between a hot reservoir at 600 K and a cold reservoir at 300 K. Calculate the maximum possible efficiency of this engine.

Accepted Answer

33.3%

Answer

50%

Answer

66.7%

Answer

100%

Question 30

Which gas is a known greenhouse gas?

Accepted Answer

Carbon dioxide

Answer

Oxygen

Answer

Nitrogen

Answer

Water vapor

Question 31

A solar panel converts solar energy directly into:

Accepted Answer

Electrical energy

Answer

Mechanical energy

Answer

Thermal energy

Answer

Chemical energy

Question 32

Which characteristic is associated with an adiabatic process?

Accepted Answer

No heat is transferred in or out of the system.

Answer

The pressure remains constant.

Answer

The volume remains constant.

Answer

The temperature remains constant.

Question 33

The operation of a refrigerator primarily relies on which principle?

Accepted Answer

The second law of thermodynamics

Answer

The first law of thermodynamics

Answer

The third law of thermodynamics

Answer

The zeroth law of thermodynamics

Question 34

Which of the following statements about heat engines is incorrect?

Accepted Answer

Heat engines operate by transferring heat from a hot reservoir to a cold reservoir.

Answer

A heat engine converts heat into mechanical work.

Answer

The efficiency of a heat engine can never exceed 100%.

Question 35

Which SI unit is used to measure temperature?

Accepted Answer

Kelvin

Answer

Celsius

Answer

Fahrenheit

Answer

Joule

Question 36

Which substance has the highest specific heat capacity?

Accepted Answer

Water

Answer

Aluminium

Answer

Steel

Answer

Wood

Question 37

During a phase change, the temperature of a substance:

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Changes unpredictably

Question 38

Which law of thermodynamics states that the entropy of an isolated system always increases?

Accepted Answer

Second law

Answer

First law

Answer

Third law

Answer

Zeroth law

Question 39

When a gas is compressed adiabatically, its temperature:

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

Becomes unpredictable

Question 40

The numerical value of a substance's specific heat capacity represents:

Accepted Answer

The heat required to raise the temperature of 1 kg of the substance by 1 K

Answer

The heat required to raise the temperature of 1 g of the substance by 1 °C

Answer

The heat required to raise the temperature of 1 mol of the substance by 1 K

Answer

The heat required to raise the temperature of 1 L of the substance by 1 °C

Question 41

Which of the following is NOT a consequence of the first law of thermodynamics?

Accepted Answer

Heat can flow spontaneously from a cold reservoir to a hot reservoir

Answer

Energy cannot be created or destroyed

Answer

The total change in the internal energy of a closed system equals the difference between the heat transferred into the system and the work done by the system

Question 42

Which of the following statements about heat engines is not true?

Accepted Answer

The Diesel cycle is a type of heat engine that uses an internal combustion process.

Answer

Heat engines convert thermal energy into mechanical energy.

Answer

The efficiency of heat engines is limited by the second law of thermodynamics.

Question 43

Which of the following is the SI unit of heat capacity?

Accepted Answer

Joule per kilogram Kelvin (J/kg K)

Answer

Celsius

Answer

Watt

Answer

Kelvin

Question 44

Thermal expansion refers to the change in a substance's:

Accepted Answer

Dimensions in response to a temperature change

Answer

Mass in response to a temperature change

Answer

Density in response to a temperature change

Answer

Shape in response to a temperature change

Question 45

Which material has the highest specific heat capacity?

Accepted Answer

Water (4187 J/kg K)

Answer

Iron (449 J/kg K)

Answer

Wood (1675 J/kg K)

Answer

Air (1005 J/kg K)

Question 46

Latent heat is the energy absorbed or released during:

Accepted Answer

A change of state (e.g., melting, freezing)

Answer

A change in temperature

Answer

A chemical reaction

Answer

A physical change (e.g., bending, stretching)

Question 47

The first law of thermodynamics states that:

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed

Answer

Entropy always increases in a closed system

Answer

Heat flows from hot objects to cold objects

Answer

The total amount of energy in a closed system remains constant

Question 48

The efficiency of a heat engine is defined as the:

Accepted Answer

Ratio of work output to heat input

Answer

Ratio of heat output to work input

Answer

Ratio of heat input to work output

Answer

Ratio of work output to heat rejected

Question 49

Which of the following is NOT a greenhouse gas?

Accepted Answer

Oxygen

Answer

Carbon dioxide

Answer

Methane

Answer

Water vapor

Question 50

Thermal radiation is:

Accepted Answer

The transfer of heat through electromagnetic waves

Answer

The transfer of heat through conduction

Answer

The transfer of heat through convection

Answer

The transfer of heat through evaporation

Question 51

Which factor does NOT affect the rate of thermal conduction?

Accepted Answer

Volume of the conductor

Answer

Temperature gradient

Answer

Cross-sectional area

Answer

Length of the conductor

Question 52

Which of the following is the SI unit of temperature?

Accepted Answer

Kelvin

Answer

Celsius

Answer

Fahrenheit

Answer

Rankine

Question 53

What is the process called when a substance changes from a solid to a liquid?

Accepted Answer

Melting

Answer

Sublimation

Answer

Evaporation

Question 54

Which substance has the highest specific heat capacity?

Accepted Answer

Water

Answer

Wood

Answer

Air

Answer

Iron

Question 55

State the first law of thermodynamics.

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Answer

Heat flows from hot to cold.

Answer

Entropy always increases.

Question 56

Which of the following processes is reversible?

Accepted Answer

Isothermal expansion of an ideal gas

Answer

Isochoric heating of a liquid

Answer

Adiabatic compression of a gas

Answer

Combustion of fuel

Question 57

Describe the relationship between the volume of a gas and its temperature at constant pressure.

Accepted Answer

Volume is directly proportional to temperature (Charles's law).

Answer

Volume is inversely proportional to temperature.

Answer

Volume is independent of temperature.

Question 58

Which material is classified as a good conductor of heat?

Accepted Answer

Copper

Answer

Wood

Answer

Plastic

Question 59

Explain the primary function of a heat exchanger.

Accepted Answer

To transfer heat between two fluids at different temperatures.

Answer

To generate electricity from heat.

Answer

To cool down electronic components.

Question 60

State the main environmental disadvantage associated with using fossil fuels as an energy source.

Accepted Answer

They release greenhouse gases that contribute to climate change.

Answer

They are expensive to extract.

Answer

They are not widely available.

Question 61

Which of the following is the unit for thermal conductivity?

Accepted Answer

W/(m⋅K)

Answer

J/(kg⋅K)

Answer

K/(W⋅m)

Answer

W/(ms)

Question 62

Which of the following is NOT a method of heat transfer?

Accepted Answer

Conduction by vacuum

Answer

Radiation

Answer

Conduction

Answer

Convection

Question 63

The specific heat capacity of a substance is

Accepted Answer

The amount of heat required to raise the temperature of 1 kg of the substance by 1 K

Answer

The temperature at which the substance melts.

Answer

The rate at which heat is transferred through the substance.

Question 64

The first law of thermodynamics states that

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Answer

Entropy always increases.

Answer

Heat always flows from hot to cold.