單項選擇題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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1.單項選擇題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

2.單項選擇題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
C.Generator rotors will have a lesser tendency to hunt
D.Because a power factor increase will decrease kilowatt output

3.單項選擇題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

4.單項選擇題When the voltage remains constant and the resistance is increased in a series circuit, the flow of current （）

A.increases by the square of the original value
B.increases
C.remains the same
D.decreases

5.單項選擇題The power factor of an AC generator operating singularly is determined by the （）

A.connected load
B.prime mover speed
C.field excitation
D.generators rated voltage