$2$c$.)$ Electrical transients prevent instantaneous responses. Say that an electric vehicle's motor can be modeled using a RL circuit $($resistor and inductor in series$).$ Kirchoff's voltage law states that the voltage of the resistor and inductor add up to any applied voltage. The voltage of a resistor is proportional to electric current. The voltage of the inductor is proportional to the rate at which current changes with time. The applied voltage is $320,$ the resistance value is $10,$ and the inductance value is $0\mathrm{.}5{10}^{-3}.$ How long will it take for the current to reach $90\%$ of its steady$-$state value if the initial current is zero?