Question

In which position (A, B, C, or D) of second charge, the flux of the electric field through the hemisphere remains uncharged? Explain.

Answer 1

If the charge is placed at A or D, any electric field line will cross the curved surface twice and there is no net influence on the flux.
At position B or C there will be more number of field lines crossing the hemisphere only once than the number of lines that cross the hemisphere twice and there will be a net influence of the flux