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ICSE Class 8 Physics Question 6 of 18

Household Electricity — Question 7

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Question

Question 7

A source of potential difference V volt sends current I ampere in a circuit for time t second. Write expressions for

(a) electrical energy supplied by the source, and

(b) electrical power spent by the source.

Answer

(a) Potential difference = V volt
Current = I ampere
time = t sec
Electrical energy supplied W = VIt

(b) Power is the rate of doing work.

P = Wt\dfrac{\text{W}}{\text{t}} = VItt\dfrac{\text{VIt}}{\text{t}} = VI

P = VI