Question

The time required for a current to attain the maximum value in a d.c. circuit containing L and R, depends upon :

• A. R only
• B. L only
• C. L/R
• D. none of these

Answer 1

The correct option is D none of these

$I=I_{max}(1-e^{-Rt/L})$

For, $I=I_{max}$

$⟹1-e^{-Rt/L}=1$

$⟹e^{-Rt/L}=0$

$⟹t=\infty$

Hence, theoretically it takes infinite time for the current to reach its maximum value.

Answer-(D)