Question

The electron gun in a television tube uses a uniform electric field to accelerate electrons from rest
to 5.0×107 m/s in a distance of 1.2 cm. What is the electric field strength?

Answer 1

Use F = E e = m a, and solve for the field E.
e is the electron charge and m is the electron mass. Use Coulombs and kg to get an answer for E in Volts per meter (which is the same as Newtons per Coulomb)

You will need to solve for the acceleration, a, first.

Use v = sqrt(2 a X) when solving for the acceleration.
X = 0.12 m
v = 5*10^7 m/s

Answer 2

2.3e12