Key Concepts: Electromagnetic Induction

Faraday's Law

• A changing magnetic flux through a loop induces an EMF (voltage).
• EMF = −dΦ/dt (Faraday's law). Φ = BA cos θ (magnetic flux).
• The induced EMF drives a current in a closed circuit.

Lenz's Law

• The induced current flows in a direction that opposes the change in flux that caused it.
• This is the reason for the negative sign in Faraday's law — it ensures energy conservation.

Ways to Induce EMF

• Change the magnetic field strength (B).
• Change the area of the loop (A).
• Change the angle between the loop and the field (θ).
• Move a conductor through a magnetic field.

Applications: Generators, transformers, induction cooktops, wireless charging.