An emf of 20V is applied at time t = 0 to a circuit containing in...

$i = {i}_{0}\left(1 - {e}^{\dfrac{- t}{L / R}}\right)$

$= \dfrac{20}{5}\left(1 - {e}^{\dfrac{- t}{0.01 / 5}}\right)$
$= 4\left(1 - {e}^{- 500t}\right)$

now at $t = \infty$
${i}_{\infty} = 4$

at $t = 40\text{s}$
${i}_{40} = 4\left(1 - {e}^{- 500 \times 40}\right)$
$= 4\left(1 - \dfrac{1}{{\left({e}^{2}\right)}^{10000}}\right) = 4\left(1 - \dfrac{1}{{7.29}^{10000}}\right)$
$\dfrac{{i}_{\infty}}{{i}_{40}} \approx 1$ Slightly greater then one.