A small 2.85 g plastic ball that has a charge q = 1.55 C is suspended by a string that has a length L = 1.00 m in a uniform electric field, as shown in the figure. A ball with charge q hangs by a string of length L from a horizontal surface. The string makes an angle of theta with the vertical, and a uniform electric field E points to the right. If the ball is in equilibrium when the string makes a θ = 9.80° angle with the vertical, what is the electric field strength E?