Deck 18: Thermodynamics

Question 1

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.

Answer 1

greater the efficiency.

Question 2

Chinook winds tend to

A)warm an environment.
B)cool an environment.
C)cool deserts at night.
D)warm deserts at sunrise.

Answer 2

warm an environment.

Question 3

Entropy measures

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

Answer 3

messiness.

Question 4

A temperature inversion occurs when the upper layers of air are

A)warmer than the lower regions of air.
B)cooler than the lower regions of air.
C)at the same temperature as lower regions of air.

Question 5

Entropy is closely related to the

A)1st law of thermodynamics.
B)2nd law of thermodynamics.
C)both of these
D)neither of these

Question 6

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.

Question 7

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.

Question 8

A volume of air has a temperature of 0 degrees Celsius.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.

Question 9

Systems that are left alone,tend to move toward a state of

A)less entropy.
B)more entropy.
C)no entropy.

Question 10

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.

Question 11

Suppose you rapidly stir some raw eggs with an eggbeater.The temperature of the eggs will

A)increase.
B)decrease.
C)remain unchanged.

Question 12

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.

Question 13

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.

Question 14

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.

Question 15

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.
E)none of these

Question 16

To totally convert a given amount of mechanical energy into heat is

A)possible.
B)impossible.
C)impossible to answer without additional information

Question 17

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.

Question 18

The lowest temperature possible in nature is

A)0 degrees C.
B)-273 degrees C.
C)4 K.

Question 19

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.

Question 20

A quantity of water has more entropy when it is

A)frozen ice.
B)boiling.
C)at room temperature.

Question 21

As a system becomes more disordered,entropy

A)increases.
B)decreases.
C)remains the same.

Question 22

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.

Question 23

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

Question 24

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

Question 25

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.

Question 26

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.

Question 27

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.

Question 28

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.

Question 29

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

Question 30

The amount of energy ultimately converted to heat by a light bulb is about

A)15%.
B)30%.
C)45%.
D)60%.
E)100%.

Question 31

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.

Question 32

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.

Question 33

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

Question 34

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.

Question 35

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.
D)594 degrees C.
E)none of these

Question 36

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.

Question 37

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.

Question 38

If a blob of air is swept upward,with no heat input or output,its temperature

A)increases.
B)decreases.
C)remains the same.

Question 39

When a system does work and no heat is added to the system,its temperature

A)increases.
B)decreases.
C)remains unchanged.

Question 40

When a volume of air is compressed and no heat enters or leaves,the air temperature will

A)increase.
B)decrease.
C)remain unchanged.

Question 41

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

Question 42

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