4.4.5

Uniform Electric Fields

Test yourself on Uniform Electric Fields

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

A Uniform Electric Field

A uniform field is one which has the same strength at every point in the field.

Uniform field

Uniform field

  • A uniform field has the same strength everywhere, it can be made from parallel charged plates.
  • If two charged plates are held a distance apart the field between them will be uniform
    • The field lines will travel straight from the positive plate into the negative plate.
Calculating the field

Calculating the field

  • If two plates are held apart with different charges they will have a voltage difference between them. The equation for the field strength is:
    • Field strength = voltage drop ÷ distance between the plates
    • E=V/dE=V/d

Work done in an Electric Field

Two oppositely charged parallel plates provide a uniform electric field. Uniform fields have field lines that are equally spaced, straight and parallel.

Moving between charged plates

Moving between charged plates

  • The work done in moving a positively charged particle from the negative plate to the positive plate is:
    • W=F×dW= F \times d
  • Where F is a constant force acting on the charged particle and d is the separation of the plates.
Derivation

Derivation

  • The work done in moving a positively charges particle is also, by definition:
    • W=Q×ΔVW = Q \times \Delta V
  • These two expressions are equal to each other:
    • F×d=Q×ΔVF\times d=Q\times \Delta V
Derivation 2

Derivation 2

  • Rearranging this gives:
    • FQ=ΔVd\frac{F}{Q}=\frac{\Delta V}{d}
  • Because FQ\frac{F}{Q} is defined as electric field strength, electric field strength between two parallel plates is:
    • E=ΔVdE = \frac{\Delta V}{d}
Jump to other topics
1

Space, Time & Motion

2

The Particulate Nature of Matter

3

Wave Behaviour

4

Fields

4.1

Circular Motion

4.2

Newton's Law of Gravitation

4.3

Fields

4.4

Fields at Work

4.5

Electric Fields

4.6

Magnetic Effect of Electric Currents

4.7

Heating Effect of Currents

4.8

Electromagnetic Induction

4.9

Power Generation & Transmission

4.10

Capacitance

5

Nuclear & Quantum Physics

6

Measurements

Practice questions on Uniform Electric Fields

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
Answer all questions on Uniform Electric Fields

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium