The Thermal Efficiency of a Reversible Heat Engine Operating Between

question 30

Multiple Choice

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP) R and the co-efficient of performance as a heat pump (COP) HP are

• A)(COP)R = (COP)HP = 0.6
• B)(COP)R = 2.5; (COP)HP = 1.5
• C)(COP)R = 1.5; (COP)HP = 2.5
• D)(COP)R = (COP)HP = 2.5

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Definitions:

Risk Premium

The extra return expected by an investor for holding a risky asset, over and above the risk-free rate.

Discount Rate

The interest rate used in calculating the present value of future cash flows. It reflects the time value of money and risk.

Real Interest Rate

The interest rate that has been adjusted to remove the effects of inflation, reflecting the real cost of funds to the borrower and the real yield to the lender or investor.

Nominal Net Cash Flow

The total amount of cash that flows into and out of a business, not adjusted for inflation.