225. Which of the following error does not result in moving iron instrument with both d.c. and a.c.?

A. stray magnetic field error

B. hysteresis error

C. eddy current error

D. temperature error.

226. VTVMs have

A. very high ohms / volt rating

B. moderate ohms / volt rating

C. low ohms / volt rating

D. very low ohms / volt rating

227. A 150 V moving iron voltmeter of accuracy class 1-0 reads 75V when used in a circuit under standard conditions. The maximum possible percentage error in the reading is

A.0.5

B.1

C.2

D.4

228. When testing a coil having a ressistance of 10 ohms, resonance occured when the oscillator frequency was 10 MHz and the rotating capacitor was set at 500 / 271 pF. The effective value of the Q of the coil is

A.200

B.254

C.314

D.542

229. A 50 Hz voltage is measured with a moving iron voltmeter and a rectifier type ac voltmeter connected in parallel. If the meter readings are V1 and V2 respectively and the meters are free from calibration errors, then the form factor of the ac voltage may be estimated as

A. V i N2

B. 1.11 V1N2

C.V1N2

D. nVi/V2

230. Consider the following statements regarding the causes of error in current transformers 1. Some exciting nunf is required by the primary winding to produce a flux 2. The flux density in the core is not a linear function of the magnetising force 3. There is some megnetic leakage in the secondary winding 4. There is significant power consumption in the metering current. Of these statements

A. 1 and 2 are correct

B. 1, 2 and 3 are correct

C. 2 and 4 are correct

D. 1, 3 and 4 are correct

231. The resistance of two coils of a wattmeter are 0-0.1 ohm and 1000 ohms respctively and both are noninductive. The load current is 20A and the voltage across the load is 30 V. In one of the two ways of connecting the voltage coil, the error in the reading would be

A. 0.1 % too high

B. 0.2% too high

C. 0.15% too high

D. zero

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