An IE Irodov Question

A ball of radius R is uniformly charged with the volume density $\large\rho$ . The flux of electric field strength vector across the ball's section formed by the plane located at a distance a<R from the center of the ball is k $\times 10^{12}$ . Then find the value of k.

VALUES: $\large\rho$ =10 a=2 R=4 $\Large\varepsilon$ = $8.85\times 10^{-12}$