Given a $60-$C point charge located at the origin, find the total electric flux passing through: $($a$)$ that portion of the sphere r $=26$ cm bounded by

$0$

$<$

$$

$<$

$$

$2$

and

$0$

$<$

$$

$<$

$$

$2$

; $($b$)$ the closed surface defined by $=26$ cm and z $=26$ cm; $($c$)$ the plane z $=26$ cm$.$

Ans. $($a$)7\mathrm{.}5$C; $($b$)60$C; $($c$)30$C