Measurements and Instrumentation

41

A peak responding ac voltmeter using a half wave rectifier has been calibrated to read 1 V for 1 V rms sine wave input. If input is 1 V dc the reading will be

A. 0.707 V
B. 0.707 or 0 V
C. 1.414 V
D. 1.414 or 0 V

42

A coil resonates at 1 MHz with a resonating capacitance of 72 pF. At 500 pF, resonance is obtained with a resonating capacitor of 360 pF. The self capacitance of coil is

A. 12 pF
B. 24 pF
C. 30 pF
D. 72 pF

43

Two wattmeter method for 3 phase power measurement can be used only for

A. balanced loads
B. unbalanced loads
C. both balanced and unbalanced loads
D. star connected loads

44

A linear displacement digital transducer generally uses

A. straight binary code
B. BCD
C. gray code
D. hexadecimal code

45

To measure an unknown ac voltage by an ac potentiometer it is desirable that supply for the potentiometer is taken

A. from a battery
B. from a source which is not the same as unknown voltage
C. from the same source as the unknown voltage
D. either (a) or (b)