Physics Question & Answer Key

A proton with an initial horizontal velocity of 2.3X10^6 m/s enters a region of uniform electric field strength of 1.1X10^5 N/C between two oppositely charge parallel plates. If the plates are 1.3cm apart and 6.7cm long, how far below the top plate must the particle be shot so as to just miss hitting the right edge of the top plate? Ignore gravitational forces.

t = d / v

   = 0.067 / (2.3e6)

   = 2.9e-8

E = F / q

F = Eq

   = (1.1e5)(1.6e-19)

   = 1.76e-14

F = ma

a = F / m

    = (1.76e-14) / (1.67e-27)

    = 1.05e13

s = ut + .5at²

   = 0 + .5(1.05e13)(2.9e-8)²

   = 0.0045 m (from top)