Question

The figure bellow shows an electron passing between two charged metal plates that create an 100 N/C vertical electric field perpendicular to the electron

Answer 1

force on elctron

F=q*E = -1.6*10^-19 *100 = -160*10^-19 N

this force will work on positive direction of y axis

so ay=F/m =160*10^-19/9.10*10^-31 = 17.58*10^12 m/s^2

ax=0 as there is no horizontal force

so time to travel 4 cm= t = 4*10^-2 /3*10^6 = 1.33*10^-8 sec

as Uy=o

vertical displacement = Sy= ay*t*t /2 = 17.58*10^12*1.33*10^-8*1.33*10^-8/2

= 15.54*10^-4 m

Vy=ay*t=17.58*10^12*1.33*10^-8 = 23.38*10^4 m/s

so , V1=sqrt(Vy^2+Vx^2) ..... as Vx=Ux

V1=sqrt((23.38*10^4)^2+(3*10^6)^2) =3009096.61 m/s

deflectionis given by

tan(theta)=Sy/Sx = 15.54*10^-4/4*10^-2 =0.000003885

theta = tan^-1(0.000003885)