The resistance of two coils of a watt-meter are 0.0 Ω and 100 Ω respectively and both are non-inductive. The current through a resistance load is 20 A and the voltage across it is 30 V. In one of the two ways of connecting the voltage coil, the error in the reading would be

One single phase wattmeter operating on 230V and 5A for 5 hours makes 1940 revolutions. Meter constant in revolutions is 400. What is the power factor of the land?

A. 1

B. 0.84

C. 0.73

D. 0.65

The spring material used in a spring control device should have the following property.

A. Should be nonmagnetic

B. Most be of low temperature coefficient

C. Should have low specific resistance

D. All of the above

Why is a MISC meter not recommended for DC measurement?

A. The meter is calibrated for AC and it’s error for DC would be high

B. The meter does not respond to DC signals

C. The error is high due to hysteresis effect

D. The error is high due to eddy current effect

A moving iron ammeter may be compensated for frequency errors by

A. A shunt resistance

B. A series inductance

C. Shunt capacitance

D. Series resistance