By what percentage will the illumination of the lamp decrease if the current drops by 20 % ?

Question

By what percentage will the illumination of the lamp decrease if the current drops by 20 % ?, 46 %, 26 %, 36 %, 56 %

MARKS App · Accepted Answer

Power through the resistor is given by, P = I 2 R . Now, P int = I 2 int R and P final = 0 .8 I int 2 R Therefore, % change in power = P final − P int P int × 100 = 0 .64 − 1 × 100 = − 36 %

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