Explanation

(a) As, $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ I = \frac{E}{R} = \frac{d\phi}{Rdt}$
or $Idt = \frac{d\phi}{R}$
Integrating
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \int_{}^{}{Idt = \int_{}^{}\frac{d\phi}{R}}$
or $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ q = \frac{\phi}{R}$
If coil contains N turns, then q $= \frac{N\phi}{R}$
If there is flux change $\Delta\phi$, then
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ q = \frac{N\Delta\phi}{R}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{1}{7} \times (1.35 - 0.79) = 0.08\ C$