Q. A variable reluctance type tachometer has 150 teeth on rotor. The counter records 13500 pulse/sec. The rotational speed is

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Q. The current through the coil of an electromagnet is doubled. The magnetic field around the coil

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Q. In a moving iron voltmeter the coil has a resistance of 20 Ω and an inductance of 0.3 H. The swamping resistance in 2000 Ω. To ensure correct reading with dc as well as 50 Hz ac, the value of capacitor to be connected in parallel with swamping resistance should be

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Q. Two resistances R1 = 18.7 Ω. and R2 = 3.624 Ω in series. The total resistance to the appropriate number of significant figures is

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Q. The input impedance of CRO is about

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Q. Which of the following is not correct in respect of electrostatic instrument?

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Q. The wave applied to X plates, for ohtaining trace of voltage wave, is

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Q. The response of a thermistor overs the whole of its temperatures range is

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Q. A resistance is measured by voltmeter-ammeter method. The voltmeter is 0-250V, ± 1% accuracy and ammeter is 0-5 A, ± 1 % accuracy. The readings of voltmeter and ammeter are 100 V and 2 A respectively. The error in the measured resistance can be

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Q. It is required to study transients during switching process. Which CRO should be preferred?

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Q. Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.

Reason (R): The resistance of electronic voltmeter is very high.

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Q. If the secondary winding of CT is opened when primary coil is carrying current

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Q. The percentage limiting error in an instrument reading 8.3 V and having guaranteed accuracy of 1% of the full scale reading and range of 0-150 V is

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Q. Consider the following features of an instrument

I. suitable for both ac and dc
II. free from hysteresis and eddy current errors
III. No waveform and frequency errors
IV. it is essentially a voltmeter

This instrument is

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Q. Which one of the following effects is used in measuring power?

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Q. The effect of lead resistance is important in measurement of

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Q. A high resistance was measured by loss of charge method. The voltmeter resistance was 10¹ᴼ ohms. The calculation gave the value of unknown resistance as 0.8 x 10⁹ ohms. The true value of resistance is

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Q. A resistance wire strain gauge has gauge factor 2. If stress is 100 mega newton/m² and Young's modulus is 200 giga newton/ m², the percentage change in gauge resistance due to stress is

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Q. The loss of charge method can be used to measure

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Q. Assertion (A): Maxwell bridge is for measuring inductance of medium magnitude.

Reason (R): In Maxwell's bridge the unknown inductance is measured by comparing it with a capacitance.

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