Question

A coil of inductanece `5H` is joined to a cell of emf `6V` through a resistance `10 Omega` at time t=0. The emf across the coil at time `t=ln sqrt(2)` s is:
A. `3 V`
B. `1.5 V`
C. `0.75 V`
D. `4.5 V`

Answer 1

Correct Answer - A
`V_(L)=Ee^(-t//tau)=Ee^(-Rt//L)=6e^(-2t)=6e^(-2xxlnsqrt(2))= 6/e^(ln(sqrt(2))^(2))=6/e^(ln^(2))=6/2=3` volt