Answer
(a) $3.8H$
(b) $0.25s$
Work Step by Step
(a) We know that
$L=\frac{-tR}{\ln(1-\frac{RI}{\mathcal{E}})}$
We plug in the known values to obtain:
$L=\frac{(0.15)(5.5)}{\ln[1-\frac{5.5(0.32)}{9.0}]}$
$L=3.8H$
(b) We know that
$t=-\frac{L}{R}\ln (1-\frac{RI}{\mathcal E})$
We plug in the known values to obtain:
$t=-(\frac{3.79}{5.5})\ln[1-\frac{(5.5)(0.50)}{9.0}]$
$t=0.25s$
