If voltage across a bulb rated 220 volt-100 Watt drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is:
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(a) 20% (b) […]
A wire having resistance 12Ω is bent in the form of an equilateral triangle. The effective resistance between any two corners of the triangle will be
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(a) 6Ω (b) 8/3Ω (c) 9Ω (d) […]
When current I is flowing through a conductor, the drift velocity is v. If the value of current through the conductor and its area of cross-section is doubled, then new drift velocity will be
A thermocouple of negligible resistance produces an e.m.f. of 40 µV/⁰C in the linear range of temperature. A galvanometer of resistance 10 ohm whose sensitivity is 1 µA/div, is employed with the thermocouple. The smallest […]
The rate of increase of thermo-e.m.f. with temperature at the neutral temperature of a thermocouple
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(a) is positive (b) is zero (c) depends upon the choice of the two materials of the […]
Two cells when connected in series are balanced on 8m on a potentiometer. If the cells are connected with polarities of one of the cells is reversed, then they balance on 2m. The ratio of […]
The thermo e.m.f. E in volts of a certain thermocouple is found to vary with temperature difference θ in ⁰C between the two junctions according to the relation E = 30θ – θ² / 15 […]
Two bulbs when connected in parallel to a source take 60W each, the power consumed, when they are connected in series with the same source is
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(a) 15W (b) 30W (c) 60W […]
The resistance of a bulb filament is 100 Ω at a temperature of 100⁰C. If its temperature coefficient of resistance be 0.005 per ⁰C, its resistance will become 200Ω at a temperature of
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Consider the following two statements: (a) Kirchhoff’s junction law follows from the conservation of charge (b) Kirchhoff’s loop law follows from the conservation of energy which is the following is correct?
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(a) […]
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