Correct Answer - C
(c)Growth in current in LR_(2) brach when switch is closed is given by
`i=(E)/(R^2)[1-e^(-R_(2)t//L)] implies (di)/(dt)=(E)/(R^2)*(R_2)/(L)e^(-R_(2)t//L)=(E)/(L)ee^(-R_(2)t/L)`
Hence, potential drop across
`L=(E/L e^(-R_(2)t//L))L=Ee^(-R_(2)t//L)=12e^(-(2t)/(400xx10^(-3)))`.