Question 1

The emissivity of an ideal reflector has which of the following values?

Accepted Answer

A)  0 
B)  1 
C)  100 
D)  infinity 
A)  0 
B)  1 
C)  100 
D)  infinity

Question 2

Marc attaches a falling 400-kg object with a rope through a pulley to a paddle wheel shaft.He places the system in a well-insulated tank holding 30 kg of water.When the object falls,it causes the paddle wheel to rotate and churn the water.If the object falls a vertical distance of 120 m at constant speed,what is the temperature change of the water? (1 kcal = 4 186 J,the specific heat of water is 4 186 J/kg⋅°C,and g = 9.8 m/s2)

Accepted Answer

A)  8,140 C° 
B)  3,700 C° 
C)  3.7 C° 
D)  0.6 C° 
E)  ​22.2 C° 
A)  8,140 C° 
B)  3,700 C° 
C)  3.7 C° 
D)  0.6 C° 
E)  ​22.2 C°

Question 3

Carbon dioxide and water molecules in the atmosphere will absorb:

Accepted Answer

A)  infrared light. 
B)  visible light. 
C)  ultraviolet light. 
D)  radio waves. 
A)  infrared light. 
B)  visible light. 
C)  ultraviolet light. 
D)  radio waves.

Question 4

The filament temperature of a light bulb is 2,000 K when the bulb delivers 40 W of power.If its emissivity remains constant,what power is delivered when the filament temperature is 2,400 K?
​

Accepted Answer

A)  166 W 
B)  125 W 
C)  83 W 
D)  62 W 
E)  ​42 W 
A)  166 W 
B)  125 W 
C)  83 W 
D)  62 W 
E)  ​42 W

Question 5

Which of the following statements is true?

Accepted Answer

A)  A hot object contains a lot of heat. 
B)  A cold object contains only a little heat. 
C)  Objects do not contain heat. 
D)  Statements a and b are true. 
A)  A hot object contains a lot of heat. 
B)  A cold object contains only a little heat. 
C)  Objects do not contain heat. 
D)  Statements a and b are true.

Question 6

A solar heating system has a 30.0% conversion efficiency;the solar radiation incident on the panels is 900 W/m2.What is the increase in temperature of 32.0 kg of water in a 1.00-h period by a 5.00-m2-area collector? (cw = 4 186 J/kg⋅°C)
​

Accepted Answer

A)  120.9°C 
B)  7.3°C 
C)  36.3°C 
D)  72.6°C 
E)  27.2°C 
A)  120.9°C 
B)  7.3°C 
C)  36.3°C 
D)  72.6°C 
E)  27.2°C

Question 7

The tungsten filament of a light bulb has an operating temperature of about 2,060 K.If the emitting area of the filament is 0.8 cm2,and its emissivity is 0.68,what is the power output of the light bulb? (σ = 5.67 × 10−8 W/m2⋅K4)
​

Accepted Answer

A)  82 W 
B)  56 W 
C)  555 W 
D)  51 W 
E)  ​48 W 
A)  82 W 
B)  56 W 
C)  555 W 
D)  51 W 
E)  ​48 W

Question 8

Pennies used to be made of copper,but now they are made of copper-coated zinc.If one were to do a precise calorimetry experiment to determine the specific heat of the new pennies,what would the result be?

Accepted Answer

A)  It would be that of copper since copper is on the outside. 
B)  It would be that of zinc since zinc is in the center. 
C)  It would be the sum of the copper and zinc specific heats. 
D)  It would be between that of copper and that of zinc,depending on coating thickness. 
A)  It would be that of copper since copper is on the outside. 
B)  It would be that of zinc since zinc is in the center. 
C)  It would be the sum of the copper and zinc specific heats. 
D)  It would be between that of copper and that of zinc,depending on coating thickness.

Question 9

Which one of the following processes of heat transfer requires the presence of a fluid?

Accepted Answer

A)  conduction 
B)  radiation 
C)  convection 
D)  none of the above choices are valid 
A)  conduction 
B)  radiation 
C)  convection 
D)  none of the above choices are valid

Question 10

A 4.00-g lead bullet is traveling at a speed of 220 m/s when it embeds in a wood post.If we assume that half of the resultant heat energy generated remains with the bullet,what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg⋅°C,1 kcal = 4 186 J)

Accepted Answer

A)  95°C 
B)  190°C 
C)  379°C 
D)  48°C 
E)  119°C 
A)  95°C 
B)  190°C 
C)  379°C 
D)  48°C 
E)  119°C

Question 11

I take 0.9 kg of ice and dump it into 0.9 kg of water and,when equilibrium is reached,I have 1.8 kg of ice at 0°C.The water was originally at 0°C.The specific heat of water = 1.00 kcal/kg⋅°C,the specific heat of ice = 0.50 kcal/kg⋅°C,and the latent heat of fusion of water is 80 kcal/kg.The original temperature of the ice was:

Accepted Answer

A)  one or two degrees below 0°C. 
B)  -80°C. 
C)  -160°C. 
D)  160°C. 
E)  ​The whole experiment is impossible. 
A)  one or two degrees below 0°C. 
B)  -80°C. 
C)  -160°C. 
D)  160°C. 
E)  ​The whole experiment is impossible.

Question 12

The surface of the Sun has a temperature of about 5,770 K.If the radius of the Sun is 7 × 108 m,determine the power output of the sun.(Take e = 1,and σ = 5.67 × 10−8 W/m2⋅K4).

Accepted Answer

A)  3.87 × 1026 W 
B)  1.23 × 1027 W 
C)  6.71 × 1022 W 
D)  2.23 × 1030 W 
E)  5.53 × 1017 W 
A)  3.87 × 1026 W 
B)  1.23 × 1027 W 
C)  6.71 × 1022 W 
D)  2.23 × 1030 W 
E)  5.53 × 1017 W

Question 13

In winter,light-colored clothes will keep you warmer than dark-colored clothes if:

Accepted Answer

A)  you are warmer than your surroundings. 
B)  you are at the same temperature as your surroundings. 
C)  you are cooler than your surroundings. 
D)  you are standing in sunlight. 
A)  you are warmer than your surroundings. 
B)  you are at the same temperature as your surroundings. 
C)  you are cooler than your surroundings. 
D)  you are standing in sunlight.

Question 14

Which type of heating causes sunburn?

Accepted Answer

A)  conduction 
B)  convection 
C)  radiation 
D)  all of the above 
A)  conduction 
B)  convection 
C)  radiation 
D)  all of the above

Question 15

As I use sandpaper on some rusty metal,the sandpaper gets hot because:

Accepted Answer

A)  heat is flowing from the sandpaper into the metal. 
B)  heat is flowing from the metal into the sandpaper. 
C)  frictional processes increase the internal energy of the sandpaper. 
D)  heat is flowing from my hand into the sandpaper. 
A)  heat is flowing from the sandpaper into the metal. 
B)  heat is flowing from the metal into the sandpaper. 
C)  frictional processes increase the internal energy of the sandpaper. 
D)  heat is flowing from my hand into the sandpaper.

Question 16

A metal bar is used to conduct heat.When the temperature at one end is 110°C and at the other is 15°C,heat is transferred at a rate of 19 J/s.If the temperature of the hotter end is reduced to 90°C,what will be the rate of heat transfer?

Accepted Answer

A)  11 J/s 
B)  6 J/s 
C)  25 J/s 
D)  15 J/s 
E)  20 J/s 
A)  11 J/s 
B)  6 J/s 
C)  25 J/s 
D)  15 J/s 
E)  20 J/s

Question 17

A machine gear consists of 0.13 kg of iron and 0.17 kg of copper.How much total heat is generated in the part if its temperature increases by 34 C°? (Specific heats of iron and copper are 450 and 390 J/kg⋅°C,respectively. )

Accepted Answer

A)  4,000 J 
B)  4,200 J 
C)  4,600 J 
D)  2,000 J 
E)  ​2,300 J 
A)  4,000 J 
B)  4,200 J 
C)  4,600 J 
D)  2,000 J 
E)  ​2,300 J

Question 18

A metal bar is used to conduct heat.When the temperature at one end is 110°C and at the other is 25°C,heat is transferred at a rate of 20 J/s.The bar is then stretched uniformly to twice its original length.If again it has ends at 110°C and 25°C,at what rate will heat be transferred between it ends?

Accepted Answer

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

Question 19

Calories of the food type are equal to which of the following?

Accepted Answer

A)  4.186 J 
B)  4 186 J 
C)  1 BTU 
D)  1054 J 
A)  4.186 J 
B)  4 186 J 
C)  1 BTU 
D)  1054 J

Question 20

An 80.0-g piece of copper,initially at 285°C,is dropped into 250 g of water contained in a 300-g aluminum calorimeter;the water and calorimeter are initially at 12.0°C.What is the final temperature of the system? (Specific heats of copper and aluminum are 0.092 0 and 0.215 cal/g⋅°C,respectively.cw = 1.00 cal/g⋅°C)

Accepted Answer

A)  29.0°C 
B)  27.8°C 
C)  6.1°C 
D)  32.5°C 
E)  5.2°C 
A)  29.0°C 
B)  27.8°C 
C)  6.1°C 
D)  32.5°C 
E)  5.2°C

Exam 11: Energy in Thermal Processes Heat and Internal Energy

The emissivity of an ideal reflector has which of the following values?

Carbon dioxide and water molecules in the atmosphere will absorb:

The filament temperature of a light bulb is 2,000 K when the bulb delivers 40 W of power.If its emissivity remains constant,what power is delivered when the filament temperature is 2,400 K? ​

Which of the following statements is true?

A solar heating system has a 30.0% conversion efficiency;the solar radiation incident on the panels is 900 W/m2.What is the increase in temperature of 32.0 kg of water in a 1.00-h period by a 5.00-m2-area collector? (cw = 4 186 J/kg⋅°C) ​

The tungsten filament of a light bulb has an operating temperature of about 2,060 K.If the emitting area of the filament is 0.8 cm2,and its emissivity is 0.68,what is the power output of the light bulb? (σ = 5.67 × 10−8 W/m2⋅K4) ​

Pennies used to be made of copper,but now they are made of copper-coated zinc.If one were to do a precise calorimetry experiment to determine the specific heat of the new pennies,what would the result be?

Which one of the following processes of heat transfer requires the presence of a fluid?

A 4.00-g lead bullet is traveling at a speed of 220 m/s when it embeds in a wood post.If we assume that half of the resultant heat energy generated remains with the bullet,what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg⋅°C,1 kcal = 4 186 J)

The surface of the Sun has a temperature of about 5,770 K.If the radius of the Sun is 7 × 108 m,determine the power output of the sun.(Take e = 1,and σ = 5.67 × 10−8 W/m2⋅K4).

In winter,light-colored clothes will keep you warmer than dark-colored clothes if:

Which type of heating causes sunburn?

As I use sandpaper on some rusty metal,the sandpaper gets hot because:

A metal bar is used to conduct heat.When the temperature at one end is 110°C and at the other is 15°C,heat is transferred at a rate of 19 J/s.If the temperature of the hotter end is reduced to 90°C,what will be the rate of heat transfer?

A machine gear consists of 0.13 kg of iron and 0.17 kg of copper.How much total heat is generated in the part if its temperature increases by 34 C°? (Specific heats of iron and copper are 450 and 390 J/kg⋅°C,respectively. )

Calories of the food type are equal to which of the following?

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

Particle Collisions, Mediating Photons, and Quark Structures: Exploring the Fundamentals of Physics

Filters

The filament temperature of a light bulb is 2,000 K when the bulb delivers 40 W of power.If its emissivity remains constant,what power is delivered when the filament temperature is 2,400 K?

A solar heating system has a 30.0% conversion efficiency;the solar radiation incident on the panels is 900 W/m².What is the increase in temperature of 32.0 kg of water in a 1.00-h period by a 5.00-m²-area collector? (c_w = 4 186 J/kg⋅°C)

The tungsten filament of a light bulb has an operating temperature of about 2,060 K.If the emitting area of the filament is 0.8 cm²,and its emissivity is 0.68,what is the power output of the light bulb? (σ = 5.67 × 10−⁸ W/m²⋅K⁴)

The surface of the Sun has a temperature of about 5,770 K.If the radius of the Sun is 7 × 10⁸ m,determine the power output of the sun.(Take e = 1,and σ = 5.67 × 10−⁸ W/m²⋅K⁴).