Electrostatics

A tiny ball of mass \(\mathrm{m}\) and charge \(\mathrm{q}\) is suspended from the fixed support using an insulating string of length \(1 \mathrm{~m}\). The horizontal uniform electric field \(\mathrm{E}\) is switched on. The angle made by the string with vertical when the ball is in equilibrium is \(45^{\circ}\). The magnitude of uniform electric field is