Q. Assertion (A): A dc potentiometer measures the true open circuit emf of a source.

Reason (R): At balance point, a dc potentiometer does not draw any current from the source.

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Q. In a CRO the Y plates are oriented

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Q. The accuracy of an instrument is determined by

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Q. If σ standard deviation, probable error

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Q. Assertion (A): In two wattmeter method of 3 phase power measurement, one of the wattmeters would read negative if power factor of load is less than 0.5.

Reason (R): In two wattmeter method of 3 phase power measurement, both the wattmeters would show equal readings if power factor of load is unity.

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Q. In a megger the moving coil meter has a permanent magnet.

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Q. The accuracy of a multimeter is about

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Q. Induction wattmeter is an absolute instrument.

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Q. In a current transformers

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Q. The time base of a high frequency CRO whose screen diameter is 10 cm is set at 10 μ sec/cm. The lowest frequency which can be fully displayed on the screen is

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Q. Eddy currents are essential for the deflecting torque of an induction wattmeter.

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Q. The output of a Piezoelectric crystal has

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Q. The pressure coil of a wattmeter should be connected to the supply side of the current coil when

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Q. A universal RLC bridge uses

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Q. If C is spring constant and θ is deflection, controlling torque is

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Q. To measure moisture in wood, the most suitable method is

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Q. An E transformer is a

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Q. In which of the following instruments is the deflecting torque proportional to dL/dQ where L is inductance of coil and Q is deflection

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Q. In a low power factor wattmeter, the resistance of pressure coil is more than in ordinary wattmeter.

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Q. The moving iron instruments are generally repulsion type.

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