单项选择题
When the current in a power transmission line is increased, the power loss （）
A.increases as the square of the current
B.decreases as the square root of the current
C.remains the same, as it is independent of current flow
D.increases in direct proportion as the current
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单项选择题
An operational amplifier, as used in todays consoles, may have a calculated gain of 5√This means that as the input changes by （）
A.1 volt, the output changes 5 volts
B.5 volts, the output changes 1 volt
C.5 volts, the output changes 10 volts
D.10 volts, the output changes 5 volts -
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Why is it desirable to operate paralleled AC generators at the same power factor?（）
A.Circulating currents are kept to a minimum
B.Field excitation losses are kept to a minimum
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An ammeter should be used to measure （）
A.the voltage between two points in a circuit
B.circuit continuity
C.current flow in a circuit
D.total or partial circuit resistance
