Faraday's Law

Part of the Electricity and Magnetism section of Coddy's Physics journey. Lesson 49 of 51.

A changing flux makes an EMF. For a coil of N turns:

$\varepsilon = N\,\frac{\Delta\Phi}{\Delta t}$

A magnet and a coil

Any change counts: the field, the area, or the angle. A steady flux gives no EMF.

Challenge

A coil of 100 turns, each of area $0.01\ \mathrm{m^2}$ , sits in a field at right angles to it. The field grows from 0 to $0.5\ \mathrm{T}$ in $0.1\ \mathrm{s}$ . What EMF $\varepsilon$ is induced?

Try it yourself

Solve for $ε$

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Electricity and Magnetism

1Electric Charge and Force

Electric Charge Coulomb's Law Several Charges Recap - Charges in a Line

4Charged Conductors

The Charged Sphere Connecting Spheres Recap - Beam Between Plates

7Real Batteries

Internal Resistance The Variable Resistor Ammeters and Voltmeters Recap - Flashlight

10Magnetic Fields

Magnets and Magnetic Fields Field of a Wire Loops and Solenoids Recap - Electromagnet

2The Electric Field

The Electric Field Field of Several Charges The Uniform Field A Charge in a Uniform Field Recap - Stopping a Proton

5Capacitors

The Capacitor Combining Capacitors Changing a Capacitor Recap - Camera Flash

8Kirchhoff's Laws

The Junction Rule The Loop Rule Solving Two Loops Recap - Charging a Battery

11Magnetic Forces

Force on a Moving Charge Circles in a Field Force on a Wire Two Parallel Wires Recap - Current Balance

3Energy and Potential

Electric Potential Energy Electric Potential Field and Potential Recap - Accelerating Ions

6Current and Resistance

Current and Voltage Resistance and Ohm's Law Series and Parallel Electric Power Recap - Fairy Lights

9Capacitors in Circuits

A Capacitor in a Circuit Charging a Capacitor Discharging a Capacitor Recap - Defibrillator

12Induction

A Rod Moving in a Field Magnetic FluxFaraday's LawLenz's Law Recap - Generator