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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Q. Assertion (A): A semiconductor strain gauge is more accurate than a resistance strain gauge.

Reason (R): The gauge factor of a semiconductor strain gauge is about 100 where as the gauge factor of a resistance strain gauge is only about 2.

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Q. Current density has the dimensions

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Q. The resistance of a dc galvanometer is 20 Ω. A current of 10 mA causes full scale deflection. To convert it into 0-300 V voltmeter, we have to use a series resistance of

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Q. The current in a circuit is measured using a 150 : 1 CT If the ammeter reads 0.6 A, the circuit current is

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Q. A volt ratio box should have low resistance.

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Q. A Hall effect transducer has KH = - 1 x 10¯⁸. If B = 1 Wb/m², I = 3 A and bismuth slab is 2 mm wide, the Hall voltage is

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Q. Two ammeters A and B both 0-10 A have internal resistance of 1 Ω and 0.5 Ω respectively. They are connected in parallel. If total current is 15 A, then

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Q. Which of the following is not correct?

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Q. Assertion (A): Thermocouple instruments can be used for ac only.

Reason (R): Thermocouple instrument has a non linear scale.

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Q. A meter has a resistance of 1 Ω and full scale deflection current of 1 mA. To convert into an ammeter of 1 A range, the shunt resistance should be

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Q. Two wattmeter method is suitable only for balanced loads.

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Q. A rectifier voltmeter using bridge rectifier and PMMC meter is calibrated to read rms value of sine wave. A triangular wave is applied to it and it reads 6.82 V. The rms value of triangular wave is

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Q. A radiation thermometer is suitable for temperatures

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Q. A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is

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Q. Wheatstone bridge is suitable for low resistances.

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Q. To avoid creep in an energy meter

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Q. A wire strain gauge has a gauge factor of 2, resistance of 125 Ω and length 1 m. If length of wire changes by .005 m, change in resistance will be

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