A point charge q is placed at the centre of a hemisphere . Find the ratio of electric flux passing through curved surface and plane surface of the hemisphere

Dear student,

Since the electric field lines coming out of the charge are spherically symmetric, the number of electric field lines passing through the curved half of the surface willl be equal to that passing throught the planar half of the hemisphere. Hence the flux passing through them is same and hence the ratio is 1:1.

Regards.