JEE Main 2016 Physics question
An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V (rms), 50 Hz AC supply, the series inductor needed for it to work is close to
Answer: (D)
Solution
R = 80/10 = 8 Ω and Z = 220/10 = 22 Ω. ≈ 20.5 Ω, so ≈ 0.065 H.