Electrons in a particle beam...?

Question

each have a kinetic energy of 1.60x10^-17J. What are the magnitude and direction of the electric field that stops these electrons in a distance of 10cm?

Answer 1

Interesting question.

Let's derive it two ways

1.

E= F*d

F=E/d

= 1.60e-17 J /10cm

= 1.60e-16 N

Electric Field = N/C

C_electron = 1.6e-19 C

Ef= 10e3 N/C = 10e3 V/m

2.  

Volts= J/C

C_electron = 1.6e-19 C

V = 10e2 Volts

Field = Volts/m

= 10e3 Volts/m