Conceptual Physics Chapter 18

Suppose the temperature of the input reservoir in a heat engine doesn't change. As the sink temperature is lowered, the efficiency of the engine A) increases. B) decreases. C) stays the same.

A) increases.

Two identical blocks of iron, one at 10 degrees C and the other at 20 degrees C, are put in contact. Suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C. This would violate the A) 1st law of thermodynamics. B) 2nd law of thermodynamics. C) both of these D) neither of these

B) 2nd law of thermodynamics.

One hundred joules of heat is added to a system that performs 60 joules of work. The internal energy change of the system is A) 0 J. B) 40 J. C) 60 J. D) 100 J. E) None of the above choices are correct.

B) 40 J.

Industrialization on Earth eventually heats our surroundings to temperatures that are higher than usual. Industrialization in space habitats using exclusively solar power eventually will thermally pollute the solar system. A) True B) False C) cannot be determined without additional information

B) False

A quantity of water has more entropy when it is A) frozen ice. B) boiling. C) at room temperature.

B) boiling.

Blow on your hand with your open mouth and you feel the warmth of your breath. Pucker your lips so your breath expands as you blow and your breath is A) warmer still. B) cooler. C) neither warmer nor cooler.

B) cooler.

Sue's refrigerator is built into the wall of her kitchen, so that it exhausts heat to the outdoors rather than into the room. If Sue tries to cool her kitchen by leaving the refrigerator door open, the room temperature will A) increase at least slightly. B) decrease at least slightly. C) remain unchanged.

B) decrease at least slightly.

When a volume of air expands against the environment and no heat enters or leaves, the air temperature will A) increase. B) decrease. C) remain unchanged

B) decrease.

If a blob of air is swept upward, with no heat input or output, its temperature A) increases. B) decreases. C) remains the same

B) decreases.

When a system does work and no heat is added to the system, its temperature A) increases. B) decreases. C) remains unchanged.

B) decreases.

A piece of iron and a cup of water both have the same temperature. If they are heated so the internal energy of each doubles A) the water will have the higher temperature. B) the iron will have the higher temperature. C) both will have the same temperature. D) not enough information given to say

B) the iron will have the higher temperature.

A temperature inversion occurs when the upper layers of air are A) cooler than the lower regions of air B) warmer than the lower regions of air C) at the same temperature as lower regions of air

B) warmer than the lower regions of air

If you run a refrigerator in a closed room with the refrigerator door open, the room temperature will A) increase. B) decrease. C) remain unchanged.

C) remain unchanged.

A volume of air has a temperature of 0 degrees C. An equal volume of air that is twice as hot has a temperature of A) 0 degrees C B) 64 degrees C C) 100 degrees C D) 273 degrees C E) none of the above choices are correct

D) 273 degrees C

To wholly convert a given amount of heat energy into mechanical energy is A) possible using a steam engine B) possible using an atomic reactor C) possible using a simple machine D) impossible regardless of the technique used

D) impossible regardless of the technique used

Adiabatic processes occur A) only in the atmosphere. B) only in the oceans C) only in the Earth's mantle. D) in both the atmosphere and the oceans E) in the atmosphere, oceans and the Earth's mantle.

D) in both the atmosphere and the oceans

More efficient gasoline engines can be built if A) engines are made to rotate faster. B) a better antifreeze is developed. C) materials are developed that can withstand lower temperatures. D) materials are developed that can withstand higher temperatures. E) None of these - they are already perfectly efficient.

D) materials are developed that can withstand higher temperatures.

The amount of energy ultimately converted to heat by a light bulb is about A) 15%. B) 30%. C) 45%. D) 60%. E) 100%.

A) 15%.

The greater the difference in temperature between the input reservoir and the output reservoir for a heat engine, the A) greater the efficiency. B) less the efficiency. C) Neither - efficiency of a heat engine doesn't depend on temperature difference.

A) greater the efficiency.

Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will A) increase. B) decrease. C) remain unchanged

A) increase.

When a volume of air is compressed and no heat enters or leaves, the air temperature will A) increase. B) decrease. C) remain unchanged.

A) increase.

As a blob of air at a high elevation sinks to a lower elevation with no heat input or output, its temperature A) increases. B) decreases. C) remains the same

A) increases.

As a system becomes more disordered, entropy A) increases. B) decreases. C) remains the same.

A) increases.

Suppose you put a closed, sealed can of air on a hot stove burner. The contained air will undergo an increase in A) internal energy, temperature and pressure. B) temperature. C) pressure. D) internal energy. E) temperature and pressure

A) internal energy, temperature and pressure.

Systems that are left alone, tend to move toward a state of A) less entropy. B) more entropy. C) no entropy.

A) less entropy.

The Earth's atmosphere gets most of its heat A) near the surface of the Earth. B) at high altitudes closer to the sun. C) from the Earth's core.

A) near the surface of the Earth.

To totally convert a given amount of mechanical energy into heat is A) possible. B) impossible. C) impossible to answer without additional information

A) possible.

Chinook winds tend to A) warm an environment. B) cool an environment. C) cool deserts at night. D) warm deserts at sunrise.

A) warm an environment.

The lowest temperature possible in nature is A) 0 degrees C. B) -273 degrees C. C) 4 K.

B) -273 degrees C.

Consider a cup of tea at room temperature, 24 degrees C. If it is heated until it has twice the internal energy, unlike a piece of metal, its temperature will be A) 48 degrees C. B) 100 degrees C. C) 321 degrees C.

B) 100 degrees C.

Entropy is closely related to the A) 1st law of thermodynamics. B) 2nd law of thermodynamics. C) both of these D) neither of these

B) 2nd law of thermodynamics.

A container of air is at atmospheric pressure and 27 degrees C. To double the pressure in the container, it should be heated to A) 54 degrees C. B) 300 degrees C. C) 327 degrees C. D) 600 degrees C. E) none of these

C) 327 degrees C.

The ideal efficiency for a heat engine operating between the temperatures of 227 degrees C and 27 degrees C is A) 20%. B) 25%. C) 40%. D) 88%. E) none of these

C) 40%.

When mechanical work is done on a system, there can be an increase in A) its internal energy. B) its temperature. C) both temperature and internal energy. D) neither temperature nor internal energy. 25) When a system does work and no heat is added to the system, its temperature A) increases.

C) both temperature and internal energy.

An adiabatic process is characterized by the absence of A) entropy. B) pressure change. C) heat exchange D) temperature change. E) None of the above choices are true.

C) heat exchange

During an adiabatic compression of an ideal gas A) the internal energy of the gas remains constant. B) the temperature of the gas does not change. C) no heat is supplied to or removed from the gas. D) no work is done on the gas. E) None of the above choices are true.

C) no heat is supplied to or removed from the gas.

Consider a piece of metal that is at 5 degrees C. If it is heated until it has twice the internal energy, its temperature will be A) 10 degrees C. B) 273 degrees C. C) 278 degrees C. D) 283 degrees C. E) 556 degrees C

D) 283 degrees C.

Consider a piece of metal that is at 10 degrees C. If it is heated until it has twice the internal energy, its temperature will be A) 20 degrees C. B) 273 degrees C. C) 293 degrees C. D) 566 degrees C. E) none of these

D) 566 degrees C.

The ideal efficiency for a heat engine operating between temperatures of 2700 K and 300 K is A) 10%. B) 24%. C) 80%. D) 89%. E) none of these

D) 89%.

The first law of thermodynamics is a restatement of the A) principle of entropy. B) law of heat addition. C) Carnot cycle. D) conservation of energy

D) conservation of energy

Entropy measures A) temperature at constant pressure. B) temperature at constant volume. C) temperature as pressure increases. D) temperature as volume increases. E) messiness.

E) messiness.

When an ideal gas is subjected to an adiabatic process A) no work is done on the gas. B) the temperature of the gas does not change. C) the internal energy of the gas does not change. D) Choices A, B, and C are all true. E) None of the above choices are true.

E) None of the above choices are true.

A heat engine would have 100 percent efficiency if its input reservoir were A) 100 times hotter than the exhaust sink. B) 1000 times hotter than the exhaust sink. C) 100 times cooler than the exhaust sink. D) any finite temperature if the exhaust sink were at absolute zero. E) at any finite temperature regardless of the heat sink temperature.

E) at any finite temperature regardless of the heat sink temperature.