Question

A Small sphere whose mass m is 1.0 x 10^-3 g carries a charge q of 2.0 x 10^-8 C. It hangs from a silk thread which makes an angle of 30 degrees with a large, charged conducting sheet as shown. Calculate the surface charge density (sigma) for the sheet. Image attached with the problem.

Answer 1

So far I got that \[\sigma = E2\epsilon_0\]
and
\[E= mgtan \theta + q\]