An electric bulb rated 100 W, 100 V has to be operated aross 141.4 V, 50 Hz A. C. supply. The

capacitance of the capacitor which has to be

connected in series with bulb so that bulb will

glow with full intensity is [NCERT Pg. 251]

The capacitance of the capacitor is 31.84 μF.

Explanation:

Given;

power rating of the bulb, P = 100 W

voltage rating of the bulb, Vr = 100 V

operating voltage of the bulb, V= 141.4 V

frequency of the AC = 50 Hz

P = IV = 100 W

V = 100 V

I =

Ic = 1 A

The voltage across the capacitor is given by;

Therefore, the capacitance of the capacitor is 31.84 μF.

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