The dynamometer principle can be used for

A)
ammeter only
B)
voltmeter only
C)
wattmeter only
D)
ammeter, voltmeter and wattmeter

Correct Answer : Option (D) :   ammeter, voltmeter and wattmeter


Explanation : Dynamometer principle can be used for ammeter, voltmeter and wattmeter. However it is generally used for wattmeters only.