$30\mathrm{.}44$ CALC A coil has $400$ turns and self$-$inductance $7\mathrm{.}50$ mH$.$

The current in the coil varies with time according to i $=$

$1680$ mA$2$ cos $1$pt$>0\mathrm{.}0250$ s$2.($a$)$ What is the maximum emf induced

in the coil? $($b$)$ What is the maximum average flux through each turn of the

coil? $($c$)$ At t $=0\mathrm{.}0180$ s$,$ what is the magnitude of the induced emf?