18.1 Faraday’s Laws; Induced Electric Fields
18.2 Lenz’s Law, Motional emf
- Lenz’s Law: The direction of induced emf (or current) is such that it always opposes the cause producing it.
- Motional emf: A conductor of length l moving with velocity v perpendicular to magnetic field B: E=Blv
18.3 A.C. Generators; Eddy Currents
18.4 Self-Inductance and Mutual Inductance
18.5 Energy Stored in an Inductor
18.6 Transformer
✅ Formula Sheet (Quick Revision)
Short Important Questions and Answers
Q1. State Faraday’s laws of electromagnetic induction.
👉 When magnetic flux through a circuit changes, emf is induced. Induced emf is proportional to rate of change of flux.
Q2. What is motional emf?
👉 Emf induced when a conductor moves through a magnetic field, E= Blv
Q3. What are eddy currents?
👉 Circulating currents induced in bulk conductors due to changing flux. Reduced by lamination.
Q4. Define self-inductance.
👉 Property of a coil by which it opposes change in current through it.
Q5. What is the energy stored in an inductor?
👉 
Q6. Write the transformer relation between voltages.
👉 
Q7. Why is AC used in transformers instead of DC?
👉 Because transformers work on mutual induction, which requires changing flux (AC).
Numerical Problems
