Q24 of 330 Page 11

The p.d. across a lamp is 12 V. How many joules of electrical energy are changed into heat and light when:

(a) a charge of 1 C passes through it?


(b) a charge of 5 C passes through it?


(c) a current of 2 A flows through it for 10 s?

As we know that


Work done = potential difference x charge


a) W= 12 ×1= 12 j


b) W= 12 ×5 = 60 j


c) W = 12 × 2 x 10 = 240 j


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