Answer & explanation
Correct answer: option 4
$ I = \frac{E}{R} e^{\frac{-tR}{L}} = 0.8\frac{E}{R}$
$ e^{\frac{-tR}{L}} = 0.8 $
$ t = \frac{ln(0.8L)}{R} = 0.016, [\frac{L}{R} = 0.01 s]$
Correct answer: option 4
$ I = \frac{E}{R} e^{\frac{-tR}{L}} = 0.8\frac{E}{R}$
$ e^{\frac{-tR}{L}} = 0.8 $
$ t = \frac{ln(0.8L)}{R} = 0.016, [\frac{L}{R} = 0.01 s]$