An ideal gas is allowed to undergo a free expansion. If its initial volume is V1 and its final volume is V2, the change in entropy is

A) nR ln (V2/V1) B) nRT ln (V2/V1) C) nk ln (V2/V1) D) 0 E) nR V2/V1 A) nR ln (V2/V1) B) nRT ln (V2/V1) C) nk ln (V2/V1) D) 0 E) nR V2/V1

Exam 22: Heat Engines, Entropy, and the Second Law of Thermodynamics

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An engine is designed to obtain energy from the temperature gradient of the ocean. What is the thermodynamic efficiency of such an engine if the temperature of the surface of the water is 59°F (15°C) and the temperature well below the surface is 41°F (5°C)?

(Multiple Choice)

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Question 41

By operating a reversible heat engine with an ideal gas as the working substance in a Carnot cycle and measuring the ratio Q_c/Q_h, we can calculate

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Question 42

The change in entropy of 1.00 kg of water that is heated from 50°C to 100°C is (in cal/K)

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Question 43

An ideal gas is allowed to undergo a free expansion. If its initial volume is V₁ and its final volume is V₂, the change in entropy is

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Question 44

What is the probability of rolling either a 7 or 11 on a single roll of a pair of dice?

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Question 45

An ideal heat engine can have an efficiency of 1 if the temperature of the low temperature reservoir is

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Question 46

A gasoline engine absorbs 2 500 J of heat and performs 1 000 J of mechanical work in each cycle. The efficiency of the engine is

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Question 47

The change in entropy of a mass m of a solid substance which has a latent heat of fusion L and melts at a temperature T is

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Question 48

For a pair of dice, how many microstates are there that result in the macrostate of rolling a 7?

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Question 49

One kilogram of chilled water at 32°F (0°C) is placed in a freezer which is kept at 0°F (−18°C). Approximately how much electric energy (in kilocalories) is needed to operate the compressor to cool this water to 0°F if the room temperature is maintained at 75°F (24°C)? (L_ice = 3.33 × 10⁵ J/kg; c_ice = 2.09 × 10³ J/kg⋅°C)

(Multiple Choice)

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Question 50

Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm³ to a final volume of 100 cm³.

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Question 51

An 800-MW electric power plant has an efficiency of 30%. It loses its waste heat in large cooling towers. Approximately how much waste heat (in MJ) is discharged to the atmosphere per second?

(Multiple Choice)

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Question 52

On a cold day, a heat pump absorbs heat from the outside air at 14°F (−10°C) and transfers it into a home at a temperature of 86°F (30°C). Determine the maximum κ of the heat pump.

(Multiple Choice)

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Question 53

All real engines are less efficient than the Carnot engine because

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Question 54

One kilogram of chilled water (0°C) is placed in a freezer which is kept at 0°F (−18°C). Approximately how much electric energy (in kilocalories) is needed just to freeze the water if the room temperature is maintained at 75°F (24°C)? (L_ice = 333 J/g; c_ice = 209 J/g⋅°C.)

(Multiple Choice)

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Question 55

Showing 41 - 55 of 55

Exam 22: Heat Engines, Entropy, and the Second Law of Thermodynamics

An engine is designed to obtain energy from the temperature gradient of the ocean. What is the thermodynamic efficiency of such an engine if the temperature of the surface of the water is 59°F (15°C) and the temperature well below the surface is 41°F (5°C)?

By operating a reversible heat engine with an ideal gas as the working substance in a Carnot cycle and measuring the ratio Qc/Qh, we can calculate

The change in entropy of 1.00 kg of water that is heated from 50°C to 100°C is (in cal/K)

An ideal gas is allowed to undergo a free expansion. If its initial volume is V1 and its final volume is V2, the change in entropy is

What is the probability of rolling either a 7 or 11 on a single roll of a pair of dice?

An ideal heat engine can have an efficiency of 1 if the temperature of the low temperature reservoir is

A gasoline engine absorbs 2 500 J of heat and performs 1 000 J of mechanical work in each cycle. The efficiency of the engine is

The change in entropy of a mass m of a solid substance which has a latent heat of fusion L and melts at a temperature T is

For a pair of dice, how many microstates are there that result in the macrostate of rolling a 7?

Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm3 to a final volume of 100 cm3.

An 800-MW electric power plant has an efficiency of 30%. It loses its waste heat in large cooling towers. Approximately how much waste heat (in MJ) is discharged to the atmosphere per second?

On a cold day, a heat pump absorbs heat from the outside air at 14°F (−10°C) and transfers it into a home at a temperature of 86°F (30°C). Determine the maximum κ of the heat pump.

All real engines are less efficient than the Carnot engine because

One kilogram of chilled water (0°C) is placed in a freezer which is kept at 0°F (−18°C). Approximately how much electric energy (in kilocalories) is needed just to freeze the water if the room temperature is maintained at 75°F (24°C)? (Lice = 333 J/g; cice = 209 J/g⋅°C.)

Physics and Measurement

Motion in One Dimension

Vectors

Motion in Two Dimensions

The Laws of Motion

Circular Motion and Other Applications of Newtons Laws

Energy of a System

Conservation of Energy

Linear Momentum and Collisions

Rotation of a Rigid Object About a Fixed Axis

Angular Momentum

Static Equilibrium and Elasticity

Universal Gravitation

Fluid Mechanics

Oscillatory Motion

Wave Motion

Superposition and Standing Waves

Temperature

The First Law of Thermodynamics

The Kinetic Theory of Gases

Electric Fields

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current and Resistance

Direct-Current Circuits

Magnetic Fields

Sources of the Magnetic Field

Faradays Law

Inductance

Alternating-Current Circuits

Electromagnetic Waves

The Nature of Light and the Principles of Ray Optics

Image Formation

Wave Optics

Diffraction Patterns and Polarization

Relativity

Introduction to Quantum Physics

Quantum Mechanics

Atomic Physics

Molecules and Solids

Nuclear Structure

Particle Physics and Cosmology

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By operating a reversible heat engine with an ideal gas as the working substance in a Carnot cycle and measuring the ratio Q_c/Q_h, we can calculate

An ideal gas is allowed to undergo a free expansion. If its initial volume is V₁ and its final volume is V₂, the change in entropy is

Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm³ to a final volume of 100 cm³.

One kilogram of chilled water (0°C) is placed in a freezer which is kept at 0°F (−18°C). Approximately how much electric energy (in kilocalories) is needed just to freeze the water if the room temperature is maintained at 75°F (24°C)? (L_ice = 333 J/g; c_ice = 209 J/g⋅°C.)