Question 1

Which of the following materials is the poorest thermal conductor?

Accepted Answer

A)  gold
B)  ice
C)  copper
D)  wood
E)  airF) None of the above
G) A) and D)

Question 2

The power radiated by a distant star is 6.2 × 1027 W. The radius of the star, which may be considered a perfect radiator, is 1.06 × 1010 m. Determine the surface temperature of the star.

Accepted Answer

A)  2970 K
B)  4630 K
C)  7440 K
D)  8710 K
E)  9970 KF) A) and C)
G) B) and E)

Question 3

A person steps out of the shower and dries off. The person's skin with an emissivity of 0.70 has a total area of 1.2 m2 and a temperature of 33 °C. What is the net rate at which energy is lost to the room through radiation by the naked person if the room temperature is 24 °C?

Accepted Answer

A)  0.041 W
B)  25 W
C)  81 W
D)  67 W
E)  47 WF) C) and D)
G) All of the above

Question 4

At what rate is heat lost through a 1.5 m × 3.0 m rectangular glass windowpane that is 0.4 cm thick when the inside temperature is 22 °C and the outside temperature is 6.0 °C? The thermal conductivity for the glass is 0.75 W/(m · C°) .

Accepted Answer

A)  560 W
B)  1800 W
C)  7200 W
D)  3600 W
E)  13 500 WF) A) and D)
G) B) and E)

Question 5

If a beaker of water is placed under a broiler so that the heating coil is above the beaker. It is observed that only the surface layer boils. The water at the bottom of the beaker remains close to the initial temperature of the water. Which of the following statements is the most reasonable conclusion to be drawn from these observations?

Accepted Answer

A)  Water is a poor conductor of heat.
B)  The sample must contain impurities.
C)  Water is easily heated by radiation.
D)  Water exhibits anomalous thermal behavior.
E)  The molecular motion in the sample is not random.F) A) and C)
G) A) and B)

Question 6

Which one of the following processes does not occur during the convective transfer of heat within a container of air?

Accepted Answer

A)  The volume of a warmed part of the air is reduced and its density increases.
B)  A continuous flow of warmer and cooler parts of air is established.
C)  The flow of air molecules results in a flow of heat.
D)  The cooler portion of the air surrounding a warmer part exerts a buoyant force on it.
E)  As the warmer part of the air moves, it is replaced by cooler air that is subsequently warmed.F) B) and C)
G) A) and B)

Question 7

Two bars, A and B, each of length 2.0 m and cross sectional area 1.0 m2, are placed end to end as shown in the figure. 2, are placed end to end as shown in the figure.   The thermal conductivities of the bars are kA = 439 J/(s . m . K)  and kB = 887 J/(s . m . K) , respectively. The left end of bar A is maintained at 373 K while the right end of B is maintained at 273 K. -Which one of the following statements is true concerning the above situation? A) For a given time t, the amount of heat transferred through bar A is the same as that through B. B) For a given time t, the amount of heat transferred through bar A is smaller than that through B. C) For a given time t, the amount of heat transferred through bar A is less than that through B. D) The time for a quantity of heat Q to pass through bar A is less than that for B. E) Time is not a factor in determining the quantity of heat conducted through these bars." class="answers-bank-image d-inline" rel="preload" > The thermal conductivities of the bars are
kA = 439 J/(s . m . K)  and kB = 887 J/(s . m . K) , respectively. The left end of bar A is maintained at 373 K while the right end of B is maintained at 273 K.
-Which one of the following statements is true concerning the above situation?

Accepted Answer

A)  For a given time t, the amount of heat transferred through bar A is the same as that through B.
B)  For a given time t, the amount of heat transferred through bar A is smaller than that through B.
C)  For a given time t, the amount of heat transferred through bar A is less than that through B.
D)  The time for a quantity of heat Q to pass through bar A is less than that for B.
E)  Time is not a factor in determining the quantity of heat conducted through these bars.F) C) and E)
G) D) and E)

Question 8

A granite wall has a thickness of 0.50 m and a thermal conductivity of 2.1 W/(m · C°) . The temperature on one face of the wall is 5.2 °C and 20.0 °C on the opposite face. How much heat is transferred in one hour through each square meter of the granite wall?

Accepted Answer

A)  2.2 × 105 J/m2
B)  1.7 × 105 J/m2
C)  7.4 × 104 J/m2
D)  1.1 × 106 J/m2
E)  62 J/m2F) All of the above
G) B) and E)

Question 9

Which of the following materials is the best thermal conductor?

Accepted Answer

A)  diamond
B)  Styrofoam
C)  nitrogen gas
D)  concrete
E)  goose downF) B) and C)
G) All of the above A

Question 10

Object A has an emissivity of 0.95; and its temperature is 25 °C. At what temperature (in degrees Celsius)  does object B, whose emissivity is 0.50, emit radiation at the same rate as object A if both objects have the same surface area?

Accepted Answer

A)  29 °C
B)  40 °C
C)  61 °C
D)  77 °C
E)  93 °CF) C) and D)
G) A) and B)

Question 11

In an experiment to determine the thermal conductivity of a bar of a new alloy, one end of the bar is maintained at 0.0 °C and the other end at 100.0 °C. The bar has a cross-sectional area of 1.0 cm2 and a length of 15 cm. If the rate of heat conduction through the bar is 34 W, what is the thermal conductivity of the bar?

Accepted Answer

A)  34 W/(m · C°) 
B)  360 W/(m · C°) 
C)  160 W/(m · C°) 
D)  510 W/(m · C°) 
E)  0.029 W/(m · C°) F) A) and E)
G) A) and D)

Question 12

Complete the following statement: The interior of a thermos bottle is silvered to minimize heat transfer due to

Accepted Answer

A)  radiation.
B)  conduction.
C)  conduction and convection.
D)  conduction and radiation.
E)  conduction, convection, and radiation.F) C) and D)
G) A) and C) A

Question 13

Which one of the following statements best explains why convection does not occur in solids?

Accepted Answer

A)  Molecules in a solid are more closely spaced than in a gas.
B)  The molecules in a solid are not free to move throughout the volume of the solid.
C)  Molecules in a solid vibrate at a lower frequency than those in a liquid.
D)  Solids are more compressible than liquids.
E)  Solids are less compressible than gases.F) C) and D)
G) A) and E)

Question 14

Two kilograms of ice at 0.0 °C are placed in a sealed glass container [k = 0.80 W/(m · C°) ]. The container is then placed in a room that is maintained at 30.0 °C. The top cover is a thermal insulator and all other sides of the container are exposed to room air. The surface area of the container is 6.53 × 10-2 m2; and its glass walls are 0.0050 m thick.
-Approximately, how long does it take all of the ice to melt?

Accepted Answer

A)  4.7 min
B)  7.8 min
C)  18 min
D)  36 min
E)  2.7 hF) All of the above
G) D) and E) D

Question 15

A cabin has a 0.159-m thick wooden floor [k = 0.141 W/(m · C°) ] with an area of 13.4 m2. A roaring fire keeps the interior of the cabin at a comfortable 18.0 °C while the air temperature in the crawl space below the cabin is -16.4 °C. What is the rate of heat conduction through the wooden floor?

Accepted Answer

A)  19 J/s
B)  138 J/s
C)  264 J/s
D)  408 J/s
E)  459 J/sF) B) and E)
G) D) and E)

Question 16

A beaker of water is placed on a Bunsen burner. As the lower layers of water are heated, they become less dense and rise. This permits cooler layers to move downward and be heated. Eventually, the water boils. Which method(s)  of heat transfer is (are)  primarily responsible for boiling the sample?

Accepted Answer

A)  conduction
B)  convection
C)  radiation
D)  both conduction and radiation
E)  both conduction and convectionF) A) and B)
G) A) and D)

Question 17

Complete the following statement: The transfer of heat by convection will occur

Accepted Answer

A)  only in metals.
B)  only in a vacuum.
C)  only in non-metallic solids.
D)  with or without the presence of matter.
E)  only in the presence of a liquid or a gas.F) A) and E)
G) B) and E)

Question 18

Suppose you are sitting next to a fire burning in a fireplace. One end of a metal poker has been left in the fire. Which one of the following statements concerning this situation is true?

Accepted Answer

A)  You can feel the heat of the fire primarily because of convection.
B)  The end of the poker that is not in the fire is warmed through conduction.
C)  Heat escapes through the chimney primarily through conduction.
D)  You can feel the heat of the fire primarily because of conduction.
E)  The end of the poker that is not in the fire is warmed through convection.F) B) and E)
G) A) and B)

Question 19

The ends of a cylindrical steel rod are maintained at two different temperatures. The rod conducts heat from one end to the other at a rate of 10 cal/s. At what rate would a steel rod twice as long and twice the diameter conduct heat between the same two temperatures?

Accepted Answer

A)  5 cal/s
B)  10 cal/s
C)  20 cal/s
D)  40 cal/s
E)  80 cal/sF) None of the above
G) All of the above

Question 20

Complete the following statement: The space between the inner walls of a thermos bottle is evacuated to minimize heat transfer by

Accepted Answer

A)  radiation.
B)  conduction.
C)  conduction and convection.
D)  conduction and radiation.
E)  conduction, convection, and radiation.F) C) and D)
G) D) and E)

Exam 13: The Transfer of Heat

Which of the following materials is the poorest thermal conductor?

Correct Answer
verified

The power radiated by a distant star is 6.2 × 10²⁷ W. The radius of the star, which may be considered a perfect radiator, is 1.06 × 10¹⁰ m. Determine the surface temperature of the star.

Correct Answer
verified

A person steps out of the shower and dries off. The person's skin with an emissivity of 0.70 has a total area of 1.2 m² and a temperature of 33 °C. What is the net rate at which energy is lost to the room through radiation by the naked person if the room temperature is 24 °C?

Correct Answer
verified

At what rate is heat lost through a 1.5 m × 3.0 m rectangular glass windowpane that is 0.4 cm thick when the inside temperature is 22 °C and the outside temperature is 6.0 °C? The thermal conductivity for the glass is 0.75 W/(m · C°) .

Correct Answer
verified

Correct Answer
verified

Which one of the following processes does not occur during the convective transfer of heat within a container of air?

Correct Answer
verified

Correct Answer
verified

A granite wall has a thickness of 0.50 m and a thermal conductivity of 2.1 W/(m · C°) . The temperature on one face of the wall is 5.2 °C and 20.0 °C on the opposite face. How much heat is transferred in one hour through each square meter of the granite wall?

Correct Answer
verified

Which of the following materials is the best thermal conductor?

Correct Answer
verified
A

Object A has an emissivity of 0.95; and its temperature is 25 °C. At what temperature (in degrees Celsius) does object B, whose emissivity is 0.50, emit radiation at the same rate as object A if both objects have the same surface area?

Correct Answer
verified

Correct Answer
verified

Complete the following statement: The interior of a thermos bottle is silvered to minimize heat transfer due to

Correct Answer
verified
A

Which one of the following statements best explains why convection does not occur in solids?

Correct Answer
verified

Correct Answer
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D

Correct Answer
verified

A beaker of water is placed on a Bunsen burner. As the lower layers of water are heated, they become less dense and rise. This permits cooler layers to move downward and be heated. Eventually, the water boils. Which method(s) of heat transfer is (are) primarily responsible for boiling the sample?

Correct Answer
verified

Complete the following statement: The transfer of heat by convection will occur

Correct Answer
verified

Suppose you are sitting next to a fire burning in a fireplace. One end of a metal poker has been left in the fire. Which one of the following statements concerning this situation is true?

Correct Answer
verified

The ends of a cylindrical steel rod are maintained at two different temperatures. The rod conducts heat from one end to the other at a rate of 10 cal/s. At what rate would a steel rod twice as long and twice the diameter conduct heat between the same two temperatures?

Correct Answer
verified

Complete the following statement: The space between the inner walls of a thermos bottle is evacuated to minimize heat transfer by

Correct Answer
verified

Exam 13: The Transfer of Heat

Which of the following materials is the poorest thermal conductor?

Correct AnswerverifiedShow Answer

The power radiated by a distant star is 6.2 × 1027 W. The radius of the star, which may be considered a perfect radiator, is 1.06 × 1010 m. Determine the surface temperature of the star.

Correct AnswerverifiedShow Answer

A person steps out of the shower and dries off. The person's skin with an emissivity of 0.70 has a total area of 1.2 m2 and a temperature of 33 °C. What is the net rate at which energy is lost to the room through radiation by the naked person if the room temperature is 24 °C?

Correct AnswerverifiedShow Answer

At what rate is heat lost through a 1.5 m × 3.0 m rectangular glass windowpane that is 0.4 cm thick when the inside temperature is 22 °C and the outside temperature is 6.0 °C? The thermal conductivity for the glass is 0.75 W/(m · C°) .

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which one of the following processes does not occur during the convective transfer of heat within a container of air?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A granite wall has a thickness of 0.50 m and a thermal conductivity of 2.1 W/(m · C°) . The temperature on one face of the wall is 5.2 °C and 20.0 °C on the opposite face. How much heat is transferred in one hour through each square meter of the granite wall?

Correct AnswerverifiedShow Answer

Which of the following materials is the best thermal conductor?

Correct AnswerverifiedA

Object A has an emissivity of 0.95; and its temperature is 25 °C. At what temperature (in degrees Celsius) does object B, whose emissivity is 0.50, emit radiation at the same rate as object A if both objects have the same surface area?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Complete the following statement: The interior of a thermos bottle is silvered to minimize heat transfer due to

Correct AnswerverifiedA

Which one of the following statements best explains why convection does not occur in solids?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedD

Correct AnswerverifiedShow Answer

A beaker of water is placed on a Bunsen burner. As the lower layers of water are heated, they become less dense and rise. This permits cooler layers to move downward and be heated. Eventually, the water boils. Which method(s) of heat transfer is (are) primarily responsible for boiling the sample?

Correct AnswerverifiedShow Answer

Complete the following statement: The transfer of heat by convection will occur

Correct AnswerverifiedShow Answer

Suppose you are sitting next to a fire burning in a fireplace. One end of a metal poker has been left in the fire. Which one of the following statements concerning this situation is true?

Correct AnswerverifiedShow Answer

The ends of a cylindrical steel rod are maintained at two different temperatures. The rod conducts heat from one end to the other at a rate of 10 cal/s. At what rate would a steel rod twice as long and twice the diameter conduct heat between the same two temperatures?

Correct AnswerverifiedShow Answer

Complete the following statement: The space between the inner walls of a thermos bottle is evacuated to minimize heat transfer by

Correct AnswerverifiedShow Answer

Correct Answer
verified

The power radiated by a distant star is 6.2 × 10²⁷ W. The radius of the star, which may be considered a perfect radiator, is 1.06 × 10¹⁰ m. Determine the surface temperature of the star.

Correct Answer
verified

A person steps out of the shower and dries off. The person's skin with an emissivity of 0.70 has a total area of 1.2 m² and a temperature of 33 °C. What is the net rate at which energy is lost to the room through radiation by the naked person if the room temperature is 24 °C?

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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A

Correct Answer
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Correct Answer
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Correct Answer
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A

Correct Answer
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Correct Answer
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D

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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