Question

In column I, some circuits are given. In all the circuits except in (i), switch S remains closed for a long time and then it is opened at $t=0$; while for (i), the situation is reversed. Column II tells something about the circuit quantities. Match the entries of column I with the entries of column II.

Answer 1

(A) if t<0 , $I_0=\frac{E}{R}$

if t>0,$I=I_0{e}^{-\frac{Rt}{L}}$ at steady state $I=0$

energy stored in the inductor=$\frac{1}{2}L{I}^2$=0

(B) Energy losses through R as heat form and finally $I=0$=$\frac{1}{2}L{I}^2$=0

(C) if t<0, $I_0=\frac{E}{R}$

if t=0,current change suddenly zero.

$\frac{1}{2}L{I}^2$=0 (dissipate in R)

Flux change very fast and induced emf

$e=-\frac{d\varphi }{dt}\simeq$ very high

$e>E$

(D) same as (C) but here when S-open,no resistance to dissipate energy in the inductor.