Question 1

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

Question 2

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 × 10S1U1P1-2S1S1P0 mS1U1P12S1S1P0; 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 h 
A) 4.7 min 
B) 7.8 min 
C) 18 min 
D) 36 min 
E) 2.7 h D

Question 3

Which of the following materials is the best thermal conductor?

Accepted Answer

A) diamond 
B) Styrofoam 
C) nitrogen gas 
D) concrete 
E) goose down 
A) diamond 
B) Styrofoam 
C) nitrogen gas 
D) concrete 
E) goose down A

Question 4

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/s 
A) 5 cal/s 
B) 10 cal/s 
C) 20 cal/s 
D) 40 cal/s 
E) 80 cal/s

Question 5

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. 
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.

Question 6

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. 
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.

Question 7

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. 
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.

Question 8

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

Question 9

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. 
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.

Question 10

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°) 
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°)

Question 11

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

Question 12

Which of the following materials is the poorest thermal conductor?

Accepted Answer

A) gold 
B) ice 
C) copper 
D) wood 
E) air 
A) gold 
B) ice 
C) copper 
D) wood 
E) air

Question 13

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

Question 14

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 W 
A) 0.041 W 
B) 25 W 
C) 81 W 
D) 67 W 
E) 47 W

Question 15

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

Question 16

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

Question 17

Two bars, A and B, each of length 2.0 m and cross sectional area 1.0 mS1U1P12S1S1P0, are placed end to end as shown in the figure.   The thermal conductivities of the bars are
kS1U1B1AS1U1B0 = 439 J/(s . m . K) and kS1U1B1BS1U1B0 = 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. 
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.

Question 18

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

Question 19

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/m2 
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/m2

Question 20

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. 
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.

Exam 13: The Transfer of Heat

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

Which of the following materials is the best thermal conductor?

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?

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?

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

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

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

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

Which of the following materials is the poorest thermal conductor?

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.

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?

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°).

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?

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?

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?

Introduction and Mathematical Concepts

Kinematics in One Dimension

Kinematics in Two Dimensions

Forces and Newtons Laws of Motion

Dynamics of Uniform Circular Motion

Work and Energy

Impulse and Momentum

Rotational Kinematics

Rotational Dynamics

Simple Harmonic Motion and Elasticity

Fluids

Temperature and Heat

The Ideal Gas Law and Kinetic Theory

Thermodynamics

Waves and Sound

The Principle of Linear Superposition and Interference Phenomena

Electric Forces and Electric Fields

Electric Potential Energy and the Electric Potential

Electric Circuits

Magnetic Forces and Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

The Refl Ection of Light: Mirrors

The Refraction of Light: Lenses and Optical Instruments

Interference and the Wave Nature of Light

Special Relativity

Particles and Waves

The Nature of the Atom

Nuclear Physics and Radioactivity

Ionizing Radiation, Nuclear Energy, and Elementary Particles

Filters

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.

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?