It is found that 10A current passes through a resistor of 10°hms. The resistor has 5% tolerance . The error in measurement of current can be as high as 5%. What is max error in measurement of power, calculated from measured value of I and the nominal value of resistor?

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