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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:

Options

  1. A0.044 H
  2. B0.065 H
  3. C80 H
  4. D0.08 H

Correct answer

B. 0.065 H

Step-by-step solution

Given that the lamp draws a current of 10   A upon a 80   V D.C. supply, the resistance is, R   =   80 10   =   8   Ω When connected to an AC supply with an inductor in series, as shown in the figure above, the current, I   =   10   A and the voltage drop over the lamp is 80   V and V L over the inductance. Applying the rules of L - R circuit, V L 2 + 80 2 = 220 2 ⇒ V L = 48400 - 6400 = 210 V The Inductive reactance of the given inductor of inductanc

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