When are two bodies in thermal equilibrium?

1. When they are in thermal contact and are at different pressures
2. When they are not in thermal contact but are at the same pressure
3. When they are not in thermal contact but are at different temperatures
4. When they are in thermal contact and are at the same temperature

What is thermal contact?

1. Two objects are said to be in thermal contact when they are in contact with each other in such a way that the transfer of energy by heat can occur between them.
2. Two objects are said to be in thermal contact when they are in contact with each other in such a way that the transfer of energy by mass can occur between them.
3. Two objects are said to be in thermal contact when they neither lose nor gain energy by heat. There is no transfer of energy between them.
4. Two objects are said to be in thermal contact when they only gain energy by heat. There is transfer of energy between them.

To which mathematical property is the zeroth law of thermodynamics similar?

1. Associative property
2. Commutative property
3. Distributive property
4. Transitive property

1. An increase in temperature causes intermolecular distances to increase.
2. An increase in temperature causes intermolecular distances to decrease.
3. An increase in temperature causes an increase in the work done on the system.
4. An increase in temperature causes an increase in the work done by the system.

The first law of thermodynamics helps us understand the relationships among which three quantities?

1. Heat, work, and internal energy
2. Heat, work, and external energy
3. Heat, work, and enthalpy
4. Heat, work, and entropy

Air freshener is sprayed from a bottle. The molecules spread throughout the room and cannot make their way back into the bottle. Why is this the case?

1. The entropy of the molecules increases.
2. The entropy of the molecules decreases.
3. The heat content (enthalpy, or total energy available for heat) of the molecules increases.
4. The heat content (enthalpy, or total energy available for heat) of the molecules decreases.

Give an example of entropy as experienced in everyday life.

1. rotation of Earth
2. formation of a solar eclipse
3. filling a car tire with air
4. motion of a pendulum bob

What is the quality by which air conditioners are judged?

1. The amount of energy generated by heat from a hot environment, compared with the required work input
2. The amount of energy transferred by heat from a cold environment, compared with the required work input
3. The amount of energy transferred by heat from a hot environment, compared with the required work output
4. The amount of energy transferred by heat from a cold environment, compared with the required work output

Why is the efficiency of a heat engine never 100 percent?

1. Some energy is always gained by heat from the environment.
2. Some energy is always lost by heat to the environment.
3. Work output is always greater than energy input.
4. Work output is infinite for any energy input.

What is a cyclic process?

1. A process in which the system returns to its original state at the end of the cycle
2. A process in which the system does not return to its original state at the end of the cycle
3. A process in which the system follows the same path for every cycle
4. A process in which the system follows a different path for every cycle

What is the advantage of a heat pump as opposed to burning fuel (as in a fireplace) for keeping warm?

1. A heat pump supplies energy by heat from the cold, outside air.
2. A heat pump supplies energy generated by the work done.
3. A heat pump supplies energy by heat from the cold, outside air and also from the energy generated by the work done.
4. A heat pump supplies energy not by heat from the cold, outside air, nor from the energy generated by the work done, but from more accessible sources.

What is thermal efficiency of an engine? Can it ever be 100 percent? Why or why not?

1. Thermal efficiency is the ratio of the output (work) to the input (heat). It is always 100 percent.
2. Thermal efficiency is the ratio of the output (heat) to the input (work). It is always 100 percent.
3. Thermal efficiency is the ratio of the output (heat) to the input (work). It is never 100 percent.
4. Thermal efficiency is the ratio of the output (work) to the input (heat). It is never 100 percent.

When would 100 percent thermal efficiency be possible?

1. When all energy is transferred by heat to the environment
2. When mass transferred to the environment is zero
3. When mass transferred to the environment is at a maximum
4. When no energy is transferred by heat to the environment

A coal power station functions at 40.0 percent efficiency. What is the amount of work it does if it takes in 1.20×10¹² J by heat?

1. 3×10¹⁰ J
2. 4.8×10¹¹ J
3. 3×10¹² J
4. 4.8×10¹³ J

A heat engine functions with 70.7 percent thermal efficiency and consumes 12.0 kJ from heat daily. If its efficiency were raised to 75.0 percent, how much energy from heat would be saved daily, while providing the same output?

1. −10.8 kJ
2. −1.08 kJ
3. 0.7 kJ
4. 7 kJ