Question 1

If the efficiency of a Carnot engine were to be $100 \%$, the heat sink would have to be

Accepted Answer

A)  at $100 ^ { \circ } \mathrm { C }$. 
B)  at $0 ^ { \circ } \mathrm { C }$. 
C)  infinitely hot. 
D)  at absolute zero. 
A)  at $100 ^ { \circ } \mathrm { C }$. 
B)  at $0 ^ { \circ } \mathrm { C }$. 
C)  infinitely hot. 
D)  at absolute zero.

Question 2

The figure shows a $p V$ diagram for $8.3 \mathrm {~g}$ of ideal nitrogen gas $\mathrm { N } _ { 2 }$ in a sealed container. The temperature of state 1 is $59 ^ { \circ } \mathrm { C }$, the atomic mass of the nitrogen atom is $14 \mathrm {~g} / \mathrm { mol }$, and $R = 8.31 \mathrm {~J} / \mathrm { mol }$ - K. What are (a) pressure $p _ { 1 }$ and (b) temperature $T _ { 2 }$ ?

Accepted Answer

A)  (a) $81 \mathrm {~atm}$, (b) $120 ^ { \circ } \mathrm { C }$ 
B)  (a) 81 atm, (b) $660 ^ { \circ } \mathrm { C }$ 
C)  (a) $14 \mathrm {~atm}$, (b) $120 ^ { \circ } \mathrm { C }$ 
D)  (a) $14 \mathrm {~atm}$, (b) $660 ^ { \circ } \mathrm { C }$ 
A)  (a) $81 \mathrm {~atm}$, (b) $120 ^ { \circ } \mathrm { C }$ 
B)  (a) 81 atm, (b) $660 ^ { \circ } \mathrm { C }$ 
C)  (a) $14 \mathrm {~atm}$, (b) $120 ^ { \circ } \mathrm { C }$ 
D)  (a) $14 \mathrm {~atm}$, (b) $660 ^ { \circ } \mathrm { C }$

Question 3

A 40.0-L container is divided into two equal parts by a rubber membrane. One half of the container has $1.50$ moles of an ideal monatomic gas at $250 \mathrm {~K}$, and the other half is a vacuum. The container is well insulated, so there is no exchange of heat with the surroundings. The membrane breaks, and eventually the gas reaches a new equilibrium condition occupying the entire volume. What is the final temperature of the gas?

Accepted Answer

A)  $125 \mathrm {~K}$ 
B)  $100 \mathrm {~K}$ 
C)  $157 \mathrm {~K}$ 
D)  $180 \mathrm {~K}$ 
E)  $250 \mathrm {~K}$ 
A)  $125 \mathrm {~K}$ 
B)  $100 \mathrm {~K}$ 
C)  $157 \mathrm {~K}$ 
D)  $180 \mathrm {~K}$ 
E)  $250 \mathrm {~K}$

Question 4

What is the change in entropy of the ice when a $0.050 - \mathrm { kg }$ ice cube at $0 ^ { \circ } \mathrm { C }$ melts? The latent heat of fusion for water is $80 \mathrm { cal } / \mathrm { g }$.

Accepted Answer

The answer of What is the change in entropy of...

Question 5

An ideal gas undergoes the process $a \rightarrow b \rightarrow c \rightarrow a$ shown in the $p V$ diagram. In the figure, $P _ { a } = P _ { C } =$ $240 \mathrm { kPa } , V _ { b } = V _ { c } = 40 \mathrm {~L} , V _ { a } = 15 \mathrm {~L}$, and $P _ { b } = 400 \mathrm { kPa }$. How much heat is gained by the gas in this $a$ $\rightarrow b \rightarrow c \rightarrow a$ process?

Accepted Answer

A)  $1500 \mathrm {~J}$ 
B)  $2500 \mathrm {~J}$ 
C)  $1000 \mathrm {~J}$ 
D)  $2000 \mathrm {~J}$ 
E)  $3000 \mathrm {~J}$ 
A)  $1500 \mathrm {~J}$ 
B)  $2500 \mathrm {~J}$ 
C)  $1000 \mathrm {~J}$ 
D)  $2000 \mathrm {~J}$ 
E)  $3000 \mathrm {~J}$

Question 6

On a cold winter day, the outside temperature is $- 20 ^ { \circ } \mathrm { C }$ and the inside temperature is maintained at $20 ^ { \circ } \mathrm { C }$. There is a net heat flow to the outside through the walls, roof, etc., of $25 \mathrm {~kW}$. At what rate is the entropy of the air outside the house changing as a result of this process?

Accepted Answer

A)  $+ 13 \mathrm {~W} / \mathrm { K }$ 
B)  $0 \mathrm {~W} / \mathrm { K }$ 
C)  $- 25 \mathrm {~W} / \mathrm { K }$ 
D)  $+ 99 \mathrm {~W} / \mathrm { K }$ 
E)  $85 \mathrm {~W} / \mathrm { K }$ 
A)  $+ 13 \mathrm {~W} / \mathrm { K }$ 
B)  $0 \mathrm {~W} / \mathrm { K }$ 
C)  $- 25 \mathrm {~W} / \mathrm { K }$ 
D)  $+ 99 \mathrm {~W} / \mathrm { K }$ 
E)  $85 \mathrm {~W} / \mathrm { K }$

Question 7

A heat engine has an efficiency of 35.0% and receives 150 J of heat per cycle.
(a) How much work does it do in each cycle?
(b) How much heat does it "waste" in each cycle?

Accepted Answer

The answer of A heat engine has an efficiency of...

Question 8

The process shown on the $p V$ diagram in the figure is

Accepted Answer

A)  isobaric. 
B)  isochoric. 
C)  isothermal. 
D)  adiabatic. 
A)  isobaric. 
B)  isochoric. 
C)  isothermal. 
D)  adiabatic.

Question 9

The figure shows a $p V$ diagram of a gas for a complete cycle. During part $b c$ of the cycle, $1190 \mathrm {~J}$ of heat flows into a system, and at the same time the system expands against a constant external pressure of $7.00 \times 10 ^ { 4 } \mathrm {~Pa}$ as its volume increases from $0.0200 \mathrm {~m} ^ { 3 }$ to $0.0800 \mathrm {~m} ^ { 3 }$. Calculate the change in internal (thermal) energy of the system during part $b c$ of the cycle. If the change is nonzero, be sure to indicate whether the change is positive or negative.

Accepted Answer

The answer of The figure shows a $p V$ diagram...

Question 10

An ideal Carnot engine operates between a warm reservoir at $233 \mathrm {~K}$ and a colder reservoir. During each cycle, this engine extracts $15.0 \mathrm {~J}$ of heat from the warm reservoir and does $4.0 \mathrm {~J}$ of work. What is the temperature of the colder reservoir?

Accepted Answer

A)  $47 \mathrm {~K}$ 
B)  $67 \mathrm {~K}$ 
C)  $62 \mathrm {~K}$ 
D)  $171 \mathrm {~K}$ 
A)  $47 \mathrm {~K}$ 
B)  $67 \mathrm {~K}$ 
C)  $62 \mathrm {~K}$ 
D)  $171 \mathrm {~K}$

Question 11

A 0.42-kg quantity of ethanol, in the liquid state at its melting point of $- 114.4 ^ { \circ } \mathrm { C }$, is frozen at atmospheric pressure. The heat of fusion of ethanol is $1.04 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { kg }$, and its molecular mass is $46.1 \mathrm {~g} / \mathrm { mol }$. What is the change in the entropy of the ethanol as it freezes?

Accepted Answer

A)  $280 \mathrm {~J} / \mathrm { K }$ 
B)  $250 \mathrm {~J} / \mathrm { K }$ 
C)  $- 280 \mathrm {~J} / \mathrm { K }$ 
D)  $- 250 \mathrm {~J} / \mathrm { K }$ 
E)  $- 310 \mathrm {~J} / \mathrm { K }$ 
A)  $280 \mathrm {~J} / \mathrm { K }$ 
B)  $250 \mathrm {~J} / \mathrm { K }$ 
C)  $- 280 \mathrm {~J} / \mathrm { K }$ 
D)  $- 250 \mathrm {~J} / \mathrm { K }$ 
E)  $- 310 \mathrm {~J} / \mathrm { K }$

Question 12

During each cycle, a heat engine takes in 4.0 J of heat, does 1.0 J of work, and expels 3.0 J
of heat. What is its efficiency?

Accepted Answer

The answer of During each cycle, a heat engine takes...

Question 13

A heat engine absorbs 64 kcal of heat each cycle and exhausts 42 kcal.
(a) What is the efficiency of this engine?
(b) How much work does this engine do per cycle?

Accepted Answer

The answer of A heat engine absorbs 64 kcal of...

Question 14

An ideal gas undergoes an isothermal expansion. During this process, its entropy

Accepted Answer

A)  increases. 
B)  decreases. 
C)  remains unchanged. 
D)  cannot be predicted from the data given. 
A)  increases. 
B)  decreases. 
C)  remains unchanged. 
D)  cannot be predicted from the data given.

Question 15

An ideal Carnot engine operates between a high temperature reservoir at $492 \mathrm {~K}$ and a river with water at $290 \mathrm {~K}$. If it absorbs $4000 \mathrm {~J}$ of heat each cycle, how much work per cycle does it perform?

Accepted Answer

A)  $2358 \mathrm {~J}$ 
B)  $1483 \mathrm {~J}$ 
C)  $1642 \mathrm {~J}$ 
D)  $2517 \mathrm {~J}$ 
A)  $2358 \mathrm {~J}$ 
B)  $1483 \mathrm {~J}$ 
C)  $1642 \mathrm {~J}$ 
D)  $2517 \mathrm {~J}$

Question 16

During an isothermal process, $5.0 \mathrm {~J}$ of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas?

Accepted Answer

A)  $10 \mathrm {~J}$ 
B)  $2.5 \mathrm {~J}$ 
C)  $5.0 \mathrm {~J}$ 
D)  $0 \mathrm {~J}$ 
A)  $10 \mathrm {~J}$ 
B)  $2.5 \mathrm {~J}$ 
C)  $5.0 \mathrm {~J}$ 
D)  $0 \mathrm {~J}$

Question 17

When $1.0 \mathrm {~kg}$ of steam at $100 ^ { \circ } \mathrm { C }$ condenses to water at $100 ^ { \circ } \mathrm { C }$, what is the change in entropy of the steam? The latent heat of vaporization of water is $22.6 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { kg }$.

Accepted Answer

A)  $22.6 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { K }$ 
B)  $- 6.1 \times 10 ^ { 3 } \mathrm {~J} / \mathrm { K }$ 
C)  zero 
D)  $6.1 \times 10 ^ { 3 } \mathrm {~J} / \mathrm { K }$ 
E)  $- 22.6 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { K }$ 
A)  $22.6 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { K }$ 
B)  $- 6.1 \times 10 ^ { 3 } \mathrm {~J} / \mathrm { K }$ 
C)  zero 
D)  $6.1 \times 10 ^ { 3 } \mathrm {~J} / \mathrm { K }$ 
E)  $- 22.6 \times 10 ^ { 5 } \mathrm {~J} / \mathrm { K }$

Question 18

A gas is taken through the cycle shown in the $p V$ diagram in the figure. During one cycle, how much work is done by the gas?

Accepted Answer

A)  $2 p _ { 0 } V _ { 0 }$ 
B)  $3 p _ { 0 } V _ { 0 }$ 
C)  $p _ { 0 } V _ { 0 }$ 
D)  $4 p _ { 0 } V _ { 0 }$ 
A)  $2 p _ { 0 } V _ { 0 }$ 
B)  $3 p _ { 0 } V _ { 0 }$ 
C)  $p _ { 0 } V _ { 0 }$ 
D)  $4 p _ { 0 } V _ { 0 }$

Exam 15: The Laws of Thermodynamics

If the efficiency of a Carnot engine were to be 100%100 \%100% , the heat sink would have to be

What is the change in entropy of the ice when a 0.050−kg0.050 - \mathrm { kg }0.050−kg ice cube at 0∘C0 ^ { \circ } \mathrm { C }0∘C melts? The latent heat of fusion for water is 80cal/g80 \mathrm { cal } / \mathrm { g }80cal/g .

A heat engine has an efficiency of 35.0% and receives 150 J of heat per cycle. (a) How much work does it do in each cycle? (b) How much heat does it "waste" in each cycle?

The process shown on the pVp VpV diagram in the figure is

During each cycle, a heat engine takes in 4.0 J of heat, does 1.0 J of work, and expels 3.0 J of heat. What is its efficiency?

A heat engine absorbs 64 kcal of heat each cycle and exhausts 42 kcal. (a) What is the efficiency of this engine? (b) How much work does this engine do per cycle?

An ideal gas undergoes an isothermal expansion. During this process, its entropy

An ideal Carnot engine operates between a high temperature reservoir at 492 K492 \mathrm {~K}492 K and a river with water at 290 K290 \mathrm {~K}290 K . If it absorbs 4000 J4000 \mathrm {~J}4000 J of heat each cycle, how much work per cycle does it perform?

During an isothermal process, 5.0 J5.0 \mathrm {~J}5.0 J of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas?

A gas is taken through the cycle shown in the pVp VpV diagram in the figure. During one cycle, how much work is done by the gas?

Introduction, Measurement, Estimating

Describing Motion: Kinematics in One Dimension

Kinematics in Two Dimensions; Vectors

Dynamics: Newtons Laws of Motion

Circular Motion; Gravitation

Work and Energy

Linear Momentum

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Static Equilibrium; Elasticity and Fracture

Fluids

Oscillations and Waves

Sound

Temperature and Kinetic Theory

Heat

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Electric Potential

Electric Currents

Dc Circuits

Magnetism

Electromagnetic Induction and Faradays Law

Electromagnetic Waves

Light: Geometric Optics

The Wave Nature of Light

Optical Instruments

The Special Theory of Relativity

Early Quantum Theory and Models of the Atom

Quantum Mechanics of Atoms

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Nuclear Energy; Effects and Uses of Radiation

Elementary Particles

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Filters

If the efficiency of a Carnot engine were to be $100 \%$ , the heat sink would have to be

What is the change in entropy of the ice when a $0.050 - \mathrm { kg }$ ice cube at $0 ^ { \circ } \mathrm { C }$ melts? The latent heat of fusion for water is $80 \mathrm { cal } / \mathrm { g }$ .

The process shown on the $p V$ diagram in the figure is

An ideal Carnot engine operates between a high temperature reservoir at $492 \mathrm {~K}$ and a river with water at $290 \mathrm {~K}$ . If it absorbs $4000 \mathrm {~J}$ of heat each cycle, how much work per cycle does it perform?

During an isothermal process, $5.0 \mathrm {~J}$ of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas?

A gas is taken through the cycle shown in the $p V$ diagram in the figure. During one cycle, how much work is done by the gas?