Answer:
Given that
speed u=4*10^6 m/s
electric field E=4*10^3 N/c
distance b/w the plates d=2 cm
basing on the concept of the electrostatices
now we find the acceleration b/w the plates to find the horizontal distance traveled by the electron when it hits the plate.
acceleration a=qE/m=[tex]1.6*10^{-19}*4*10^3/9.1*10^{-31} =0.7*10^{15}[/tex]=[tex]7*10^{14}[/tex] m/s
now we find the horizontal distance traveled by electrons hit the plates
horizontal distance
[tex]X=u[2y/a]^{1/2}[/tex]
=[tex]4*10^6[2*2*10^{-2}/7*10^{14}]^{1/2}[/tex]
=[tex]3*10^{-2}[/tex]= 3 cm