A small sphere whose mass is 0.60 g carries a charge of 3.0 x 10-9 C and is attached to one end of a silk fiber 8.00 cm long. The other end of the fiber is attached to a large vertical conducting plate, which has a surface charge of 25.0 x 10-6 C/m2 on each side. Find the angle the fiber makes with the vertical plate when the sphere is in equilibrium.