Question

When an RL circuit is connected to a battery, which is true about its initial and final states?
A. It initially acts like a broken wire and finally acts like ordinary connecting wire.
B. It initially acts like ordinary connecting wire and finally acts like a broken wire.
C. It acts like broken wire throughout the charging.
D. It acts like ordinary connecting wire throughout the charging.

Answer 1

Answer:A

Explanation:

In R-L circuit current is given by

$i=i_0\left [ 1-e^{\frac{-t}{L/R}}\right ]$

where i=current at any time t

$i_0=maximum\ current$

R=resistance

L=Inductance

at t=0 $e^{\frac{-t}{L/R}}$ approaches to 1

therefore $i=i_0\left [ 1-1\right ]$

i=0

when t approaches to $\infty$,  $e^{\frac{-t}{L/R}}$ approaches to zero

thus $i=i_0$

thus we can say that initially circuit act as broken wire with zero current

and it increases exponentially with time and act as ordinary connecting wire