Phys_2C_W06_Q4_A

# Phys_2C_W06_Q4_A - 3 4 A heat pump with a COP of 4.7...

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PHYS 2C, W 2006 QUIZ #4 Version A Name___________________________________ Code______________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question 1) A Carnot engine operates between temperatures T 1 and T 2 > T 1 . Suppose a third reservoir is available whose temperature can be any desired number between T 1 and T 2 . It comes with another Carnot engine that can be used to make a two - stage machine. What is the maximum efficiency it can achieve? A) (T 2 - T 1 )/(2 T 2 ) B) 1 - (T 1 /T 2 ) 2 C) (T 2 - T 1 )/(T 2 +T 1 ) D) 1 - (T 1 /T 2 ) 1) 2) In which of the processes shown below the heat received by the ideal gas is the smallest? A) 1 B) 2 C) 3 D) 4 2) 3) What is the efficiency of a Carnot engine operating between a reservoir in which ice and water coexist, and a reservoir in which water and steam coexist? The pressure is at 1.0 atm for both. A) 0.27% B) 27% C) 100% D) 1.0%

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Unformatted text preview: 3) 4) A heat pump with a COP of 4.7 absorbs heat from the atmosphere at a rate of 14 kW. At what rate is it doing work? A) 66 kW B) 3 kW C) 17 kW D) 52 kW 4) 5) A 9.0-mol monoatomic ideal gas at 312.0 K does a free adiabatic expansion (W = Q = 0) until its volume increases 10.0-fold. What is the change in entropy? Express your answer in terms of R. The formula for the entropy of an ideal gas is S = nR ln[(V/n) T 3/2 ] + const. A) 21 R J/K B) 6500 R J/K C) 28,000 R J/K D) 0.0 R J/K 5) 6) 15.0 kg of mercury (specific heat 140 J/kg · K) is heated from 301.0 K to 346.0 K. How much does entropy increase? Use the formula for the entropy of a system with a constant heat capacity. A) 47 J/K B) 95,000 J/K C) 290 J/K D)-0.91 J/K 6) Answer Key Testname: PHYS 2C W06 QUIZ 4 1) D 2) A 3) B 4) B 5) A 6) C...
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Phys_2C_W06_Q4_A - 3 4 A heat pump with a COP of 4.7...

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