Chapter 4: Q59P (page 781)
A small sphere with mass 1.50 g hangs by a thread between two very large parallel vertical plates 5.00 cm apart (Fig. P23.59). The plates are insulating and have uniform surface charge densities +and -. The charge on the sphere is. What potential difference between the plates will cause the thread to assume an angle of 30.0° with the vertical?
Short Answer
The potential difference between the plates V = 47.75V