This uses the concept of electric current developed in Subtopic 2.1: Potential difference and electric current.
Magnetic flux (Φ) is defined as the product of magnetic field strength (B) and the area perpendicular to the magnetic field (A⊥). Hence: 
⊥
- Solve problems involving the use of ⊥
Videos: Flux and magnetic flux
Electromagnetic induction is the process in which a changing magnetic flux induces a potential difference in a conductor.
The induced potential difference is referred to as an electromotive force (ε).
The changing magnetic flux is due to relative movement of the conductor or variation of the magnetic field strength.
Faraday’s Law states that the induced emf is equal to the rate of change of the magnetic flux.
For N conducting loops the induced ε is given by 
Lenz’s Law states that the direction of a current created by an induced is such that it opposes the change in magnetic flux producing the ε.
• Solve problems involving the induction of an ε in a straight conductor.
• Solve problems involving the induction of an ε in N conducting loops.
• Use the law of conservation of energy to explain Lenz's Law.
• Use Lenz’s Law to determine the direction of the current produced by the induced ε.
• Use Lenz's Law to explain the production of eddy currents.
Video: Potential Difference vs. emf
Simulation: Faraday's Law
Video: Induction - Crash Course
Video: Electromagnetic Induction
Video: Lenz's Law (Khan Academy) | Lenz's Law (Do Online Now Guys)
Video: Eddy Currents
Notes: Eddy Currents
Some generators use a fixed magnet to generate emfs in rotating conducting loops for electricity production.
• Explain how generators can be used to produce an alternating electric current.
Simulation: Faraday's Lab (choose Generator)
Video: Simple explanation of a generator
Video: How Power Gets to Your Home (to 2:17)
Transformers allow generated voltage to be either increased or decreased before it is used. A transformer consists of an input coil (with Ninput turns) with a potential difference Vinput and an output coil
(with Noutput turns) with a potential difference Voutput.
The relationship between the potential differences is given by the formula:
• Describe the purpose of transformers in electrical circuits.
• Explain how a transformer increases or decreases an alternating potential difference.
• Compare step-up and step-down transformers.
• Solve problems involving the use of:
Video: Electricity Distribution
Simulation: Faraday's Lab (choose Transformer)
Video: How Power Gets to Your Home (from 3:40)