: The switch has been in the a position for a long time. At $=0$ the switch is thrown from position a to position b$.$ a$)$ Determine the initial current in the inductor. b$)$ Determine the time constant of the circuit for $0$ c$)$ Find i$,1,$ and $2$ for $0.$ d$)$ What percentage of the initial energy stored in the inductor is dissipated in the $90$ resistor $1$ ms after the switch is thrown from position a to position b$?$