Deck 7: Heat Transfer and Change of Phase

Question 1

If you were caught in freezing weather with only a candle for warmth, you would be warmer in

A)an igloo.
B)a tent.
C)a wooden house.

Answer 1

A

Question 2

The process of convection occurs in

A)solids.
B)liquids.
C)gases.
D)fluids.
E)none of the above

Answer 2

D

Question 3

Hot steam that issues from a pressure cooker expands and

A)increases in temperature.
B)can cause severe burns.
C)cools.
D)all of the above
E)none of the above

Answer 3

C

Question 4

The gush of steam that issues from the escape valve of a pressure cooker is relatively cool

A)above the opening where expansion is prominent.
B)close to the opening.
C)none of the above

Question 5

A poor conductor of heat is a

A)poor insulator.
B)good insulator.
C)neither

Question 6

Metals are both good heat and electrical conductors due to

A)similar thermal and electrical conductive properties.
B)looseness of outer electrons in metal atoms.
C)relatively high densities of metals.
D)high elasticity of metals.
E)ability of metals to transfer energy easily.

Question 7

When a volume of air is compressed, its temperature

A)increases.
B)decreases.
C)neither

Question 8

Convection currents in the air near a seashore are produced by

A)shifting winds.
B)unequal heating of land and water.
C)varying temperatures.
D)none of the above

Question 9

One of the main reasons people can walk barefoot on red-hot coals of wood without burning their feet has to do with

A)low temperature of the coals.
B)low thermal conductivity of the coals.
C)mind over matter techniques.

Question 10

A water-filled paper cup held in a flame will not catch fire because

A)the inside of the paper is wet.
B)water is an excellent conductor of heat.
C)paper is a good conductor of heat.
D)the paper cup cannot become appreciably hotter than the water it contains.

Question 11

Your toes feel warmer on a rug than on a tile floor because the rug

A)is usually warmer than tile.
B)is a better insulator than tile.
C)has more thermal energy than tile.
D)all of the above
E)none of the above

Question 12

A good insulator

A)slows heat transfer.
B)prevents heat transfer.
C)quickens heat transfer.

Question 13

Write a short paragraph distinguishing between conduction and convection. Give two examples of each.

Question 14

Warm air rises because faster moving molecules tend to move to regions of less

A)density.
B)pressure.
C)both

Question 15

Radiant energy emitted by our planet is

A)terrestrial energy.
B)the result of radioactivity in Earth's interior.
C)electromagnetic.
D)all of the above

Question 16

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)still warm.
B)cooler.
C)neither

Question 17

A substance absorbs heat energy by the process of

A)conduction.
B)convection.
C)radiation.
D)none of the above

Question 18

Coastal winds shift from night to day due to

A)conduction.
B)convection.
C)radiation.
D)all about equally.

Question 19

A good heat conductor is a

A)poor insulator.
B)good insulator.
C)neither

Question 20

If a volume of air is warmed, it expands. If a volume of air expands, it

A)warms.
B)cools.
C)neither

Question 21

Objects that are good radiators generally

A)absorb radiation relatively well.
B)reflect radiation relatively well.
C)both
D)neither

Question 22

The Sun's radiant energy is composed of shorter wavelengths than the Earth's because the Sun

A)has much more thermal energy.
B)has a higher temperature than the Earth.
C)is an energy source while the Earth is primarily an energy receiver.
D)none of the above

Question 23

Hot water will cool to room temperature faster in a

A)black pot.
B)silver pot.
C)depends on size, not color.

Question 24

The average frequency of radiant energy is directly proportional to the

A)Celsius temperature of the emitter.
B)Fahrenheit temperature of the emitter.
C)kelvin temperature of the emitter.
D)all of the above
E)none of the above

Question 25

The silver coating on the glass surfaces of a Thermos bottle reduces energy that is transferred by

A)conduction.
B)convection.
C)radiation.
D)friction.
E)none of the above

Question 26

The pupil of your eye is a net

A)absorber of radiant energy.
B)emitter of radiant energy.
C)neither

Question 27

Cold water will warm to room temperature faster in a

A)black pot.
B)silver pot.
C)depends on size, not color.

Question 28

If air were a better conductor than it is, nighttimes on Earth would be

A)considerably colder.
B)considerably warmer.
C)not appreciably different in temperature.

Question 29

To minimize heat loss it is best that a teapot be

A)black.
B)silver.
C)depends on size, not color.

Question 30

A star that is twice as hot as another has twice the

A)Celsius temperature.
B)Fahrenheit temperature.
C)kelvin temperature.
D)any of the above
E)none of the above

Question 31

The higher the frequency of a wave, the

A)shorter the wavelength.
B)longer the wavelength.
C)neither

Question 32

The higher the temperature of an object, the

A)higher frequency it radiates.
B)lower frequency it radiates.
C)none of the above

Question 33

A good reflector of radiation is a

A)good absorber of radiation.
B)good emitter of radiation.
C)poor absorber of radiation.
D)none of the above

Question 34

If a poor absorber of radiation were a good emitter, its temperature would be

A)less than its surroundings.
B)more than its surroundings.
C)the same as its surroundings.

Question 35

Which emits the highest frequency of radiation?

A)a red-hot star
B)the Sun
C)a blue-hot star
D)all the same

Question 36

The higher the temperature of an object, the

A)longer the wavelengths it radiates.
B)shorter the wavelengths it radiates.
C)none of the above

Question 37

A good absorber of radiation is a

A)good emitter of radiation.
B)poor emitter of radiation.
C)good reflector.
D)none of the above

Question 38

If an object radiates more energy than it reflects, its

A)thermal energy decreases.
B)temperature decreases.
C)both
D)neither

Question 39

If an object radiates more energy than it absorbs, its

A)thermal energy decreases.
B)temperature decreases.
C)both
D)neither

Question 40

An object will normally be a net radiator of energy when its temperature is

A)higher than its surroundings.
B)lower than its surroundings.
C)neither

Question 41

Compared to a glass of ice water with ice, a glass of plain ice-cold water without ice on a warm day will warm up

A)faster.
B)slower.
C)in the same amount of time.

Question 42

If the greenhouse effect on Earth were absent, Earth's average temperature would be about

A)-18°C.
B)appreciably warmer.
C)as it is now.

Question 43

On sunny days, why do hot-air balloons suddenly rise when they drift over a wide road or parking lot made of black asphalt?

Question 44

Glass in a florist's greenhouse blocks radiation of

A)high frequency.
B)low frequency.
C)all frequencies.

Question 45

Transparency of the atmosphere is lowest for radiation of

A)infrared light.
B)visible light.
C)ultraviolet light.

Question 46

A friend says that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling

A)supports this statement.
B)shows this statement is false.
C)none of the above

Question 47

Heating the Earth's atmosphere is caused by energy

A)production.
B)consumption.
C)both
D)neither

Question 48

Why does a good emitter of heat radiation appear black at room temperature?

Question 49

A red-hot piece of iron will cool faster in a

A)cold room.
B)warm room.
C)same in each.

Question 50

A can of soft drink will cool faster if placed in what part of a refrigerator?

A)the freezer compartment
B)the main part of the refrigerator
C)both locations should cool the can at the same rate

Question 51

To say you can never change only one thing means that when you change something,

A)something else changes.
B)only one other thing will change.
C)you can't do it again.

Question 52

Suppose you want to save energy and you're going to leave your cool house for a half hour on a hot day. You should turn the temperature setting on the air conditioner

A)down.
B)up.
C)off.
D)to room temperature.

Question 53

Suppose you are served coffee at a restaurant before you are ready to drink it. In order for it to be the hottest when you are ready for it, you should add cream

A)right away.
B)at any time.
C)when you are ready to drink the coffee.

Question 54

Which is not a phase of matter?

A)solids
B)liquids
C)gases
D)vacuum

Question 55

Suppose you want to save energy and you're going to leave your warm house for a half hour on a cold day. You should turn the thermostat

A)down.
B)up.
C)off.
D)to room temperature.

Question 56

The Earth loses heat mainly by

A)conduction.
B)convection.
C)radiation.
D)none of the above

Question 57

Explain why white clothing helps keep us cool, whereas black clothing helps to warm us. Which is the better reflector? Which is the better absorber?

Question 58

Glass and the atmosphere are largely opaque to

A)infrared light.
B)visible light.
C)ultraviolet light.

Question 59

The interior of a greenhouse emits long-wavelength radiation due to its

A)green color.
B)plant cell structure.
C)transparency.
D)temperature.

Question 60

Newton's law of cooling applies to objects that are

A)cooling.
B)warming.
C)both
D)none of the above

Question 61

If molecules in a sample of gas moved so they completely missed each other, the gas's temperature would

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

Question 62

A soda pop can with a small amount of water is on a hot stove. Soon steam comes from its opening. When the can is quickly inverted into a pan of water, the can is crushed by

A)suction of the can interior.
B)condensation.
C)atmospheric pressure.
D)a drop in pressure.

Question 63

To say that evaporation is a cooling process is to say that the

A)water left behind cools.
B)surrounding air cools.
C)condensation is minimum.

Question 64

When evaporation occurs in a dish of water, the molecules left behind in the water

A)are less energetic.
B)have decreased average speeds.
C)result in lowered temperature.
D)none of the above

Question 65

Sublimation is a change of phase from solid to gas without

A)passing through the liquid phase.
B)a transfer of energy.
C)a change of temperature.

Question 66

A mixture of light and heavy molecules make up a sample of gas. The temperature of the gas is constant, which means all the molecules have the same average

A)speed.
B)kinetic energy.
C)both
D)none of the above

Question 67

At the same temperature, which move with the greater speed in a gas?

A)light molecules
B)heavy molecules
C)both have equal average speeds

Question 68

The dew that forms on a cold soda can when taken from a refrigerator is due to

A)evaporation.
B)condensation.
C)sublimation.
D)none of the above

Question 69

Pigs wallow in mud mainly to

A)decrease thermal conductivity.
B)shield themselves from the Sun.
C)cool themselves by evaporation.

Question 70

A hot dog pants

A)to help evaporation occur in its mouth and bronchial tract.
B)to bring more oxygen into its lungs.
C)for no particular reason-some things just happen.
D)to impress dogs of the opposite sex.

Question 71

Put a saucer of water on your table. A process that occurs in the saucer is

A)evaporation.
B)condensation.
C)both
D)neither

Question 72

Both heavy and light molecules make up a sample of gas. On average, the faster molecules are the

A)heavy ones.
B)light ones.
C)no difference
D)not enough information

Question 73

The molecules in a room-temperature glass of water jostle around at

A)a great variety of speeds.
B)much the same speeds.
C)constant speeds.

Question 74

In a gaseous mixture of hydrogen and oxygen, the molecules having the greatest average kinetic energy are

A)hydrogen.
B)oxygen.
C)both the same.
D)not enough information

Question 75

In a gaseous mixture of hydrogen and oxygen, the faster molecules on average are

A)hydrogen.
B)oxygen.
C)both the same.
D)not enough information

Question 76

In a gaseous mixture of hydrogen and oxygen, the higher-temperature molecules are

A)hydrogen.
B)oxygen.
C)both the same
D)not enough information

Question 77

Consider a steaming aluminum soda-pop can that contains a small amount of boiling water. When it is quickly inverted into a bath of cooler water, the can is dramatically crushed. This is due to the rapidly reduced pressure inside the can by

A)contact with the relatively cool water.
B)sudden slowing of the air and steam molecules inside.
C)condensation of steam inside.
D)reduced thermal energy.
E)rapid conduction of heat to the relatively cool water.

Question 78

From a molecular point of view, explain why evaporation is a cooling process. What cools?

Question 79

Evaporation is a cooling process because

A)heat is radiated during the process.
B)of conduction and convection.
C)the more energetic molecules are able to escape the liquid.
D)the temperature of the remaining liquid decreases.
E)none of the above

Question 80

In a gaseous mixture of hydrogen and oxygen, the slower molecules on average are

A)hydrogen.
B)oxygen.
C)both the same.
D)not enough information