A coil of inductance 8.4 mH and resistance `6 (Omega)` is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time

Options

A. 500s
B. 25 s
C. 35 s
D. 1 ms

Answer

D

Explanation

Using `I=(I_0)(1-e^(-t//tau))`
But`(I_0)=V/R and (tau)=L/R`
`:. I=V/R (1-e^(-t//tau))=12/6[1-e^(-6t//8.4xx(10^3))]`
`=1(given)`
`:. T=0.97xx(10^(-3))s~~1 ms`.