Question

An electric bulb marked 25 W and 100 V is connected across 50 V supply. Now its power is
(1) 25 W
(2) 12.5 W
(4) 50 W
(3) 6.25 W
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Answer 1

Answer : 6.25W (3) is correct option

Answer 2

Answer:

6.25kW

Explanation:

since power = VI= V^2/R

R = V^2/P

now as the bulb resistance remains same in both case

(100)^2/25 = (50)^2/P

P = 25/4 = 6.25kW