Solving a problem in physics section 73 point 33 electr

33. A thread is attached to a vertically located infinite uniformly charged plane, on the other end of which there is a ball of the same name with a mass of m = 40 mg and a charge of q = 31.8 nC. The tension force of the thread on which the ball hangs, T = 0.5 mN. Find the surface charge density σ in the plane. The dielectric constant of the medium in which the charge is ε = 6. Acceleration of gravity g = 10 m / s2.