190. A meter has a full-scale deflection of 90? at a current of 1A. The response of the meter is square law. Assuming spring control, the current for a deflection at 45? will be
A. 0.25 A
B. 0.50 A
C. 0.67 A
D. 0.707 A
191. A permanent magnet moving coil type ammeter and a moving iron type ammeter are connected in series in a resistive circuit fed from output of a half wave rectifier voltage source. If the moving iron type instrument reach 5 A, the permanent magnet moving coil type instrument is likely to read
A. zero
B. 2.5 A
C. 3.18A
D. 5A
192. A compensated wattmeter has its reading corrected for error due to
A. frequency
B. friction
C. power consumed in current coil
D. power consumed in potential coil
193. While measuring power in a three phase load by two wattmeter met hod;, the reading of the two wattmeter will be equal and opposite when
A. power factor is unity
B. load is balanced
C. phase angle is between 60? and 90?
D. load is purely inductive
194. A polarized electrolytic capacitor can be used
A. only in sinusoidal circuits
B. in dc and sinusoidal ac circuits
C. only in dc circuit
D. in circuit having any arbitrary waveform of current
195. The major cause of creeping in an energy meter is
A. over-compensation for friction
B. mechanical vibrations
C. excessive voltage across the potential coil
D. stray magnetic field
196. The Lissajous pattern obtained on a CRO screen is shown in the given figure. The frequency ratio of the vertical signal to the horizontal signal is
A. 20 V to 40 V
B. 24 V to 36 V
C. 29.4 V to 30.6 V
D. 29.94 to 30.06 V
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