76.

77.

78.

79.

80.

098/23

Asymmetrical sawtooth wave form has an amplitude of +100 V is applied to full wave
rectifier type AC voltmeter. The meter reading will be

A) 70.71 V 8) 57.73 V

C) 63.66 V D) 55.50 V

If aaQ—2A moving iron ammeter has an internal resistance of 100 mQ and inductance
of 0.1 mH. A shunt coil is used to extend its range to 0 — 20 A for all operating
frequencies. The time constant in milliseconds and resistance in MQ of the shunt
coil respectively are

A) 1, 5.55 8) 1, 11.11
C) 2,10 0) 2,11

The current through the moving iron instrument has increased by 30%, what is the
percentage increase in the deflection torque ?

A) 30 B) 50
C) 69 D) 60

A single-phase energy meter is measuring the energy consumption of a unity power
factor constant load for 2 hours. If the meter disc makes 2300 revolutions for a 230 V,
20 A load current, what will be the meter constant ?

A) 1000 B) 250
C) 125 D) 500

Two in phase 50 Hz sinusoidal wave forms of Peak-to-peak value 2 V is fed into
the channel-1 and channel-2 respectively of an oscilloscope. If the voltage scale, time
scale and other settings are exactly the same for both the channels. What would be
observed Lissajous pattern if the oscilloscope is operated in X-Y mode ?

A) A circle of unit radius

B) An ellipse

C) A circle of two unit radius

D) A straight line inclined at 45° with respect to the x axis

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