A toroid has a rectangular cross$-$section of a$\backslash$times b

with a$=2$cm and b$=3$cm$,$ inner radius of R$=$

$4$ cm $,$ number to turns N$=320,$ and has a

current of I$($t$)=12\mathrm{.}5$sin$(377$t$)$ amps. What is

the voltage inducted $($has a function of time$)$ in

a secondary coil with turns of N$^(\text{'})=52$