posted by Isabell .
An electron in a computer monitor enters midway between two parallel oppositely charged plates. The initial speed of the electron is 6.15 x 10^7 m/s and its vertical deflection is 4.70 mm. (a) What is the magnitude of the electric field between the plates? (b) Determine the magnitude of the surface charge density on the plates in C/m^2. The length of the plates are 10 cm and the width of the plates are 1 cm.