Question 1

Which one of the following is a true statement?

Accepted Answer

A) The second law of thermodynamics is a consequence of the first law of thermodynamics. 
B) It is possible for thermal energy to flow spontaneously from a hot body to a cold one or from a cold one to a hot one, depending on whether or not the process is reversible or irreversible. 
C) It is not possible to convert work entirely into thermal energy. 
D) It is impossible to transfer thermal energy from a cooler to a hotter body. 
E) All of these statements are false. 
A) The second law of thermodynamics is a consequence of the first law of thermodynamics. 
B) It is possible for thermal energy to flow spontaneously from a hot body to a cold one or from a cold one to a hot one, depending on whether or not the process is reversible or irreversible. 
C) It is not possible to convert work entirely into thermal energy. 
D) It is impossible to transfer thermal energy from a cooler to a hotter body. 
E) All of these statements are false.

Question 2

Two ideal Carnot thermodynamic engines have the same efficiency.One operates between 5.0 × 102 K and 3.0 × 102 K,and the other between 4.0 × 102 K and some lower temperature.What is the lower temperature?

Accepted Answer

A) 200 K 
B) 220 K 
C) 240 K 
D) 260 K 
E) 280 K 
A) 200 K 
B) 220 K 
C) 240 K 
D) 260 K 
E) 280 K

Question 3

A nuclear power plant has an actual efficiency of 33%.If $0.19 \mathrm { MW }$ of energy are released from fission,how much electric power does the power plant produce?

Accepted Answer

A) 0.063 MW 
B) 6.3 MW 
C) 25 MW 
D) 0.25 MW 
A) 0.063 MW 
B) 6.3 MW 
C) 25 MW 
D) 0.25 MW

Question 4

The ocean thermal energy conversion project uses the surface water near tropical islands with a temperature of 20°C as the hot temperature reservoir,and the water at some depth,with a temperature of 5.0°C,as the cold temperature reservoir for a thermodynamic engine.What is the maximum possible efficiency of an engine running between those two temperatures?

Accepted Answer

A) 4.7% 
B) 5.1% 
C) 7.9% 
D) 15% 
E) 30% 
A) 4.7% 
B) 5.1% 
C) 7.9% 
D) 15% 
E) 30%

Question 5

A thermodynamic engine with an efficiency of 30% performs 2500 J of work.How much thermal energy is discharged to the lower temperature reservoir?

Accepted Answer

A) 5800 J 
B) 8300 J 
C) 750 J 
D) 1400 J 
E) 7100 J 
A) 5800 J 
B) 8300 J 
C) 750 J 
D) 1400 J 
E) 7100 J

Question 6

A thermodynamic engine absorbs 85.6 kJ of energy each cycle and exhausts 61.8 kJ.
(a)What is the efficiency of the engine?
(b)How much work does it do each cycle?

Accepted Answer

(a)27.8%

Question 7

A thermodynamic engine having the maximum possible efficiency has an efficiency of 25% when operating between two heat reservoirs.If the temperature of the cold reservoir is 300 K,what is the temperature of the hot reservoir?

Accepted Answer

A) 350 K 
B) 375 K 
C) 400 K 
D) 450 K 
E) 500 K 
A) 350 K 
B) 375 K 
C) 400 K 
D) 450 K 
E) 500 K

Question 8

During each cycle of operation,a refrigerator absorbs 230 J of energy from the freezer and expels 356 J of energy to the room.How much work input is required in each cycle?

Accepted Answer

A) 712 J 
B) 586 J 
C) 460 J 
D) 126 J 
A) 712 J 
B) 586 J 
C) 460 J 
D) 126 J

Question 9

A thermodynamic pump with a performance coefficient (COP)of 4.9 absorbs thermal energy from the atmosphere at a rate of $29 \mathrm {~kW} \text {. }$ At what rate is work being done to run this thermodynamic pump?

Accepted Answer

A) 6 kW 
B) 142 kW 
C) 113 kW 
D) 35 kW 
A) 6 kW 
B) 142 kW 
C) 113 kW 
D) 35 kW

Question 10

A coal-fired plant generates 600 MW of electric power.The plant uses 4.8 × 106 kg of coal each day,and the heat of combustion of coal is 3.3 × 107 J/kg.The steam that drives the turbines is at a temperature of 300°C,and the exhaust water is at 37°C.
(a)What is the overall efficiency of the plant for generating electric power?
(b)How much thermal energy is exhausted each day?
(c)Using the same heat reservoirs,what is the maximum possible efficiency for a thermodynamic engine?

Accepted Answer

(a)33% 
(b

Which one of the following is a true statement?

Two ideal Carnot thermodynamic engines have the same efficiency.One operates between 5.0 × 10² K and 3.0 × 10² K,and the other between 4.0 × 10² K and some lower temperature.What is the lower temperature?

A nuclear power plant has an actual efficiency of 33%.If $0.19 \mathrm { MW }$ of energy are released from fission,how much electric power does the power plant produce?

A thermodynamic engine with an efficiency of 30% performs 2500 J of work.How much thermal energy is discharged to the lower temperature reservoir?

A thermodynamic engine absorbs 85.6 kJ of energy each cycle and exhausts 61.8 kJ. (a)What is the efficiency of the engine? (b)How much work does it do each cycle?

A thermodynamic engine having the maximum possible efficiency has an efficiency of 25% when operating between two heat reservoirs.If the temperature of the cold reservoir is 300 K,what is the temperature of the hot reservoir?

During each cycle of operation,a refrigerator absorbs 230 J of energy from the freezer and expels 356 J of energy to the room.How much work input is required in each cycle?

A thermodynamic pump with a performance coefficient (COP)of 4.9 absorbs thermal energy from the atmosphere at a rate of $29 \mathrm {~kW} \text {. }$ At what rate is work being done to run this thermodynamic pump?

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

Exam 14: Second Law of Thermodynamics

Which one of the following is a true statement?

Two ideal Carnot thermodynamic engines have the same efficiency.One operates between 5.0 × 102 K and 3.0 × 102 K,and the other between 4.0 × 102 K and some lower temperature.What is the lower temperature?

A nuclear power plant has an actual efficiency of 33%.If 0.19MW0.19 \mathrm { MW }0.19MW of energy are released from fission,how much electric power does the power plant produce?

A thermodynamic engine with an efficiency of 30% performs 2500 J of work.How much thermal energy is discharged to the lower temperature reservoir?

A thermodynamic engine absorbs 85.6 kJ of energy each cycle and exhausts 61.8 kJ. (a)What is the efficiency of the engine? (b)How much work does it do each cycle?

A thermodynamic engine having the maximum possible efficiency has an efficiency of 25% when operating between two heat reservoirs.If the temperature of the cold reservoir is 300 K,what is the temperature of the hot reservoir?

During each cycle of operation,a refrigerator absorbs 230 J of energy from the freezer and expels 356 J of energy to the room.How much work input is required in each cycle?

A thermodynamic pump with a performance coefficient (COP)of 4.9 absorbs thermal energy from the atmosphere at a rate of 29 kW. 29 \mathrm {~kW} \text {. }29 kW. At what rate is work being done to run this thermodynamic pump?

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

Two ideal Carnot thermodynamic engines have the same efficiency.One operates between 5.0 × 10² K and 3.0 × 10² K,and the other between 4.0 × 10² K and some lower temperature.What is the lower temperature?

A nuclear power plant has an actual efficiency of 33%.If $0.19 \mathrm { MW }$ of energy are released from fission,how much electric power does the power plant produce?

A thermodynamic pump with a performance coefficient (COP)of 4.9 absorbs thermal energy from the atmosphere at a rate of $29 \mathrm {~kW} \text {. }$ At what rate is work being done to run this thermodynamic pump?