Chapter 6 Multiple choice questions

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. Section 6.2 describes early steam engines. What was James Watt's key invention that improved their efficiency?

The use of very high pressure steam correct incorrect

Compound cylinders correct incorrect

A separate condenser correct incorrect

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. How big is a horsepower in kilowatts?

0.5 kW correct incorrect

About 0.75 kW correct incorrect

1.2 kW correct incorrect

1.4 kW correct incorrect

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. Section 6.3 describes the principles of heat engines. Box 6.3 describes temperature scales and Carnot's formula. The size of a degree is the same in the Celsius and Kelvin scales but how do you convert between the scales?
Temperature in kelvins =

degrees Celsius + 273.15. correct incorrect

same as the temperature in degrees Celsius. correct incorrect

degrees Celsius + 100. correct incorrect

degrees Celsius - 32. correct incorrect

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. Hot steam enters an engine at 177 degrees Celsius and is condensed to water at 27 degrees Celsius. What will be the Carnot efficiency of such an engine?

40% correct incorrect

33.3% correct incorrect

30% correct incorrect

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. Section 6.3 also describes the three Laws of Thermodynamics. What does the Second Law say?

There is an absolute zero of temperature below which nothing can be cooled. correct incorrect

The efficiency of a heat engine is always less than 100%. correct incorrect

Energy can neither be created nor destroyed (only changed from one form to another). correct incorrect

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. Section 6.4 describes the age of steam. Box 6.5 describes the important properties of fluids such as water under pressure. What is atmospheric pressure approximately, expressed in units of megapascals?

10 megapascals correct incorrect

1 megapascal correct incorrect

One tenth of a megapascal correct incorrect

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. Water boils at 100 degrees Celsius at atmospheric pressure. What happens to the boiling point as the pressure is increased?

It increases. correct incorrect

It stays the same. correct incorrect

It decreases. correct incorrect

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. What happens to water above a temperature of 374 degrees Celsius and a pressure of 22 megapascals?

It dissociates into hydrogen and oxygen. correct incorrect

Its boiling point decreases. correct incorrect

The distinction between water and steam disappears. correct incorrect

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. Section 6.5 describes power station turbine systems. How fast does a typical large power station turbine rotate?

500 - 600 revolutions per minute correct incorrect

1500 - 3500 revolutions per minute correct incorrect

18 000 revolutions per minute correct incorrect

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. Section 6.6 describes power station turbine systems. A cooling tower cools which element of a power station system?

The condenser correct incorrect

The generator correct incorrect

The boiler correct incorrect