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Copper and Silicon are cooled from 300 K to 60 K. The specific resistance

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Important Questions on Current Electricity

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A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of...
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The temperature coefficient of resistance of a wire is 0.00125 per degree Celsius. At 300 K its resistance is 1 ohm. The resistance of the wire will be 2 ohm at a temperature:-

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The current-voltage graph for a given metallic conductor at two different temperatures T1 and T2 are shown in the figure. Then:-

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At what temperature will the resistance of a copper wire become three times its value at 0 °C? [Temperature coefficient of resistance for copper=4×10-3 per °C]
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A resistor develops 500 J of thermal energy in 20 s when a current of 1.5 A is passed through it. If the current is increased from 1.5 A to 3 A, what will be the energy developed in 20 s.
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A current of 2 A flowing through a conductor produces 80 J of heat in 10 s. The resistance of the conductor is 
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Some electric bulbs are connected in series across a 220 V supply in a room. If one bulb is fused, then remaining bulbs are connected again in series across the same supply. The illumination in the room will:

 

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How many electrons flow per second through an electric bulb rated 220 V, 100 W ?