$9\mathrm{.}6$ A $2-$m long center$-$fed dipole antenna operates in the AM broadcast band at $1$ MHz$.$ The dipole is made of copper wire with a radius of $1$ mm$.$

$($a$)$ Determine the radiation efficiency of the antenna.

$*($b$)$ What is the antenna gain in decibels?

$($c$)$ What antenna current is required so that the antenna will radiate $80$ W$,$ and how much power will the generator have to supply to the antenna?