Sanju
Last Activity: 6 Years ago
Here we can treat the charge on sphere 2, & the charge within R/2 in sphere 1, to be at the centers of the spheres. If q1 and q2 are both positive (or both negative), they can cancel at P. We can then equate the magnitudes of the forces:
q2 / (3R/2)2 = q1*(1/2)3 / (r/2)2
where some constants are cancelled, and charge within R/2 in sphere 1 is q1/8.
Then simplifying the above eqn,
q2/q1 = 9/8.