AnswersPhysicsSecond Law of Thermodynamics

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Which statement describes the relationship between energy and entropy in the universe?

A
Energy must be decreased for entropy to be constant.
B
Energy must be destroyed for entropy to be constant.
C
Energy must be created to increase entropy.
D
Energy must be added to decrease entropy.
2
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Answer:

entropy

5

What is the formula for calculating the efficiency of a heat engine?

A
mathrm cap e f f i c i e n c y is equal to the fraction with numerator cap t sub h minus cap t sub c and denominator cap t sub h times 100
B
mathrm cap e f f i c i e n c y is equal to the fraction with numerator cap t sub c minus cap t sub h and denominator cap t sub h times 100
C
mathrm cap e f f i c i e n c y is equal to the fraction with numerator cap t sub c minus cap t sub h and denominator cap t sub c times 100
D
mathrm cap e f f i c i e n c y is equal to the fraction with numerator cap t sub h minus cap t sub c and denominator cap t sub c times 100
6

Which is the best example of increasing entropy?

A
A pile of library books is placed in a neat stack on a shelf.
B
A dining room is cleaned to remove dust.
C
A deserted field becomes overgrown with weeds.
D
A cyclist pedals harder while riding uphill.
7

The temperature of a heat engine is 500 cap k Some of the heat generated by the engine flows to the surroundings, which are at a temperature of 125 cap k

Answer:

75

8

Dierdra began writing a summary of the relationship between the first and second laws of thermodynamics. Thermal energy in a system is conserved and can increase the system’s internal energy and/or be used to do work. Which best completes Dierdra’s summary?

A
Thermal energy is created when it enters the system.
B
Thermal energy moves from cooler objects to warmer objects
C
Thermal energy is destroyed when it leaves the system.
D
Thermal energy moves from warmer objects to cooler objects.
9

Rosa pours a cup of boiling water into a pot of room-temperature water. According to the second law of thermodynamics, what will occur?

A
Thermal energy from the room-temperature water will continuously flow to the boiling water.
B
Thermal energy from the room-temperature water will flow to the boiling water until all of the water in the pot is at a single temperature.
C
Thermal energy from the boiling water will flow to the room-temperature water until all of the water in the pot is at a single temperature.
D
Thermal energy from the boiling water will continuously flow to the room-temperature water.

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