Constantan wire is used in making standard resistances because its (a) Specific resistance is low (b) Density is high (c) Temperature coefficient of resistance is negligible (d) Melting point is high

100 mA current gives a full scale deflection in a galvanometer of 2Ω resistance. The resistance connected with the galvanometer to convert it into a voltmeter to measure 5V is

(a) 98 Ω

(b) 52 Ω

(d) 48 Ω

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A solid sphere, a hollow sphere and a disc, all having same mass and radius, are placed at the top of an incline and released. The friction coefficients between the objects and the incline are same and not sufficient to allow pure rolling. Least time will be taken in reaching the bottom by:

The solid sphere.
The hollow sphere.
The disc.
All will take same time.

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Find the equivalent resistance across AB

(a) 1 W

(b) 2 W

(d) 4 W

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Which quantity decrease in step-down transformer ?

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A house is served by 220 V supply line in a circuit protected by a 9 ampere fuse. The maximum number of 60 W lamps in parallel that can be turned on, is

(a) 44

(b) 20

(d) 33

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Certain radio-active substance reduces to 25% of its value in 16 days. Its half-life is

(a) 32 days

(b) 8 days

(d) 28 days

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The rays of different colours fail to converge at a point after going through a converging lens. This defect is called:

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Which of the following is correct?