Question
A simple and common technique for accelerating electrons is shown in Figure 18.55, where there is a uniform electric field between two plates. Electrons are released, usually from a hot filament, near the negative plate, and there is a small hole in the positive plate that allows the electrons to continue moving. (a) Calculate the acceleration of the electron if the field strength is $2.50 \times 10^4 \textrm{ N/C}$. (b) Explain why the electron will not be pulled back to the positive plate once it moves through the hole.
Question Image Figure 18.55 Parallel conducting plates with opposite charges on them create a relatively uniform electric field used to accelerate electrons to the right. Those that go through the hole can be used to make a TV or computer screen glow or to produce X-rays.
1. $4.39 \times 10^{15} \textrm{ m/s}^2$
2. The net electric field outside of the plates is zero. See the solution video for an explanation as to why.
Solution Video

# OpenStax College Physics Solution, Chapter 18, Problem 53 (Problems & Exercises) (3:08)  