A charge `q_0` is distributed uniformly on a ring of radius R. A sphere of equal radius R constructed with its centre on the circumference of the ring. Find the electric flux through the surface of the sphere.

Explanation

`C_1` is the centre of charged ring and `C_2` is the centre of sphere. `C_1C_2=R, PC_1=PC_2=R`, hence `anglePC_1C_2=60^@`. Now it can be understood that the part of ring subtending `120^@` of angle at centre `C_1` is enclosed inside sphere. Hence , charge enclosed within the sphere is Q/3. Using Gauss.s law we can write electric flux
`=q_"in"/epsilon_n=Q/(3epsilon_0)`.