Faraday’s Law

By BT and TP

What is Faradays law

• Faraday's law of induction is a basic law of electromagnetism relating to the operating principles of transformers, inductors, and many types of electrical motors and generators.

EMF

• The induced electromotive force (emf) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit.

How Faraday’s Law Combines With Lenz’s Law

If Faraday’s Law shows how to calculate the induced emf and Lenz’s Law shows the direction of the induced current you can combine the two equations to get.ε

ε = Blv

The law..

• Faraday’s law of electromagnetic induction states that the induced emf in a circuit is equal to the rate of change of flux linkage throughout the circuit.

ε = Bl/Δt = Blv

Test

• A rectangular coil of length 40mm and width 25mm has 20 turns. The coil is in a uniform magnetic field of 68mT. What is the flux linkage when coil is perpendicular to field lines?

• 1.4 mWb

• The coil is removed in 60ms. Calculate the mean reduced emf?

• 23mW

Click for answers