Answer: 10.36 N.m^2/C
Explanation: In order to calculate the electric flux through the hole drilled in the non conductive sphere which sorrounds a charge: Firstly we have to calculate the electric field at the radius of the sphere
To do that we have to use the Gaussian Law as:
∫E.dS= Total charge inside/ε0
E. Area= Qinside/ε0
E=Q/(4πR^2ε0)=3.3 10^6 N/C
After that we calculate the flux through the hole of 1 mm radius as follows:
E. Ahole= 3.3 10^6*π* (0,18)^2 =10.36 Nm^2/C