1. A dc wattmeter essentially consists of
A. two ammeters
B. a voltmeter and an ammeter
C. two voltmeters
D. a current and a potential transformer
2. High ac voltages are usually measured with
A. electrostatic voltmeters
B. voltmeter and current transformer
C. potential transformer and voltmeter
D. voltmeter and multiplier
3. A moving-coil instrument can be used to measure
A. low frequency a.c.
B. high frequency a.c.
C. direct current
D. d.c. and a.c. both
4. The resistance of a field coil may be correctly measured by using
A. a voltmeter and an ammeter
B. Schering bridge
C. a Kelvin double bridge
D. a Maxwell bridge
5. Which of the following instrument will be used to measure alternating current only?
A. moving-iron voltmeter
B. permanent-magnet type ammeter
C. induction-type ammeter
D. moving-iron (attraction-type) ammeter.
6. When connecting wattmeters to a load circuit consuming large current, it is necessary o use
A. potential transformers
B. isolation transformers
C. power shunts
D. current transformers
7. Which of the following electrical equipment cannot convert ac into dc?
A. diode
B. converter
C. transformer
D. mercury-arc rectifier
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