An electrical power plant manages to send 90 of the heat produced in the burning of fossil fuel into the water-to-steam conversion. Of the heat carried by the steam, 40 is converted to the mechanical energy of the spinning turbine. Which of the following choices best describes the overall efficiency of the heat-to-work conversion in the plant (as a percentage)?
a. greater than 90
b. 65
c. less than 40
d. 40
e. 90
[Ques. 2] If R1 < R2 < R3, and if these resistors are connected in series in a circuit, which one dissipates the greatest power?
a. R1
b. R2
c. R3
d. All are equal in power dissipation.
[Ques. 3] A heat engine operating between a pair of hot and cold reservoirs with respective temperatures of 400 K and 200 K will have what maximum efficiency?
a. 50
b. 50
c. 40
d. 45
e. 25
[Ques. 4] Three resistors, each with resistance R1, are in series in a circuit. They are replaced by one equivalent resistor, R. Comparing this resistor to the first resistor of the initial circuit, which of the following is true?
a. The current through R equals the current through R1.
b. The voltage across R equals the voltage across R1.
c. The power given off by R equals the power given off by R1.
d. R is less than R1.
[Ques. 5] A heat engine exhausts 3 200 J of heat while performing 1 500 J of useful work. What is the efficiency of the engine?
a. 68
b. 32
c. 16
d. 50
e. 84
[Ques. 6] Three resistors, with values of 1.0, 4.0, and 10.0 , respectively, are connected in series. What is the overall resistance of this combination?
a. 0.7
b. 5.0
c. 4.0
d. 15
[Ques. 7] A gas expends to three times its original volume, and in the process no energy is transferred to the gas. What happens to the internal energy of this gas?
a. It increases.
b. It decreases.
c. It remains constant.
d. Impossible to know without more information
[Ques. 8] Three resistors with values of R1, R2 and R3, respectively, are connected in series. Which of the following expresses the total resistance, RT, of the three resistors?
a. RT = R1 + R2 + R3
b. RT = (1/R1 + 1/R2 + 1/R3)
c. RT = R1 = R2 = R3
d. RT = (1/R1 + 1/R2 + 1/R3)1
[Ques. 9] For a monatomic gas, 3R/2 is
a. the specific heat per mole at constant volume.
b. the specific heat per unit mass at constant volume.
c. NAkB.
d. none of the above.
[Ques. 10] Three resistors connected in series have individual voltages labeled V1, V2 and V3, respectively. Which of the following expresses the value of the total voltage VT taken over the three resistors together?
a. VT = V1 + V2 + V3
b. VT = (1/V1 + 1/V2 + 1/V3)
c. VT = V1 = V2 = V3
d. VT = (1/V1 + 1/V2 + 1/V3)1
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