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Question
I ampere of current is passed through a resistor of resistance R ohm for time t second. Obtain expression for
(i) the electrical energy, and
(ii) the electrical power spent.
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Solution
The potential difference across the resistor V = IR volt
Charge passed in resistor Q = It coulomb
(i) Work was done (or the electrical energy spend) in passing charge Q coulomb through the resistor at potential difference V volt = QV joule
= (It) × (IR) = I2Rt joule.
(ii) Electrical power spent = `"Energy"/"Time" = ("I"^2"Rt")/"t"` = I2R watt.
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