232. In the statement "the wattmeter commonly used for power measurement at commercial frequencies is of the 2i type. This meter consists of two coil systems, the fixed system being the X coil and moving system being coil". x, Y and Z stand respectively for

A. dynamometer, voltage and current

B. dynamometer, current and voltage

C. induction, voltage and current

D. induction, current and voltage

233. Two-wattmeter method is employed to measure power in a 3-phase balanced system with the current coils connected in the A and C lines. The phase sequence is ABC. If the wattmeter with its current coil in A-phase line reads zero, then the power factor of the 3-phase load will be

A. zero lagging

B. zero leading

C. 0.5 lagging

D. 0.5 leading

234. The shunt type ohmeter is NOT suitale for high resistance measurements because

A. a very low resistance of the meter would short the high unknown resistance

B. scale is highly cramped for high resistance values

C. full-scale value of the meter may be exceeded

D. battery cannot supply the necessary current for proper meter detection.

235. A galvanometer is tested shown in figure, in the circuit where E = 1.5 V, 111 = 1.0 ohm, R2 = 2500 ohm and R3 is variable. With R3 set at 450 ohm, the galvanometer deflection is 140 mm and with R3 set at 950 ohm, the galvanometer deflection is 70 mm. The resistance of the galvanometer is

A.500

B.750

C.1000

D.1500

236. The measurement of very low and very high frequences is invariably done using a frequency counter / timer in the

A. frequency measurement mode only

B. period measurement mode only

C. frequency and period measurement modes respectively

D. period and frequency measurement modes respectively.

237. In the particular form of frequency meter, 1p, F capacitor is conne ted across a symmetrical square wave signal of IV peak value. If the average value of the current taken by the capacitor, after full wave rectification is measured as 2 mA, then the frequency of the signal will be

A. 1000/7tHz

B. 500 Hz

C. 1000 Hz

D. 1000 it Hz.

238. The meter constant of a single-phase 240 V induction wathour meter is 400 revolutions per kWh. The speed of the meter disc for a current of 10 amperes of 0.8 p.f. lagging will be

A. 12.8 rpm

B. 16.02 rmp

C. 18.2 rpm

D. 21.1 rpm.

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