# The electron gun in a television tube uses a uniform electric field to accelerate electrons from...

## Question:

The electron gun in a television tube uses a uniform electric field to accelerate electrons from rest to {eq}4.1 \times 10^7 {/eq} m/s in a distance of 1.4 cm.

Part A

What is the electric field strength?

## Force due to an electric field

First, we use the kinematic equation {eq}v^2 = u^2+2aS {/eq} to find the acceleration of electron to travel the given distance from rest.

Then we apply Newton's Second Law({eq}F = ma {/eq}) and compare the result with the definition of force in terms of an electric field,

{eq}F = qE {/eq}

where,

**q** is the charge of the electron,

**E** is the magnitude of the electric field.

## Answer and Explanation:

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View this answerGiven:

- Velocity of the electron(
**{eq}v {/eq}**) = {eq}4.1\times 10^7\ \text{m/s} {/eq}

- Distance(
**S**) = {eq}1.4\ \text{cm} = 0.014\ \text{m} {/eq}

We...

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Chapter 14 / Lesson 12The electric force is one of the most powerful, fundamental forces in the universe. In this lesson, we will learn how charged objects exert electric forces on each other and how to calculate the strength of that force.