Question

An inductor coil stores U energy when i current is passed through it and dissipates energy at the rate of P. The time constant of the circuit, when the coil is connected across a battery of zero internal resistance is

(A) \(\frac{4U}{P}\) 

(B) \(\frac UP\)

(C) \(\frac{2U}P\)

(D) \(\frac{2P}U\)

Answer 1

Correct option is (C) \(\frac{2U}{P}\)

\(\frac1 2 LI^2 = U\)

\(I^2 R = P \)

\(T = \frac LR = \frac{2U}P\)