⚡ EMI Complete Notes + Quiz (JEE 2026)

📘 Electromagnetic Induction (Detailed Theory)

Electromagnetic Induction: When magnetic flux linked with a circuit changes, an EMF is induced.

Magnetic Flux: It is the number of magnetic field lines passing through an area.

Φ = B A cosθ

Faraday's First Law: EMF is induced when flux changes.

Faraday's Second Law: Magnitude of EMF is proportional to rate of change of flux.

E = - dΦ/dt

Lenz Law: Direction of induced current opposes cause (energy conservation).

⚡ Motional EMF (Most Important)

When conductor moves in magnetic field, EMF is generated.

E = B l v

Direction → Fleming Right Hand Rule

🔁 Self Inductance

Property of coil to oppose change in current.

E = -L (dI/dt)
L = NΦ / I

🔗 Mutual Inductance

Change in current in one coil induces EMF in another.

⚡ Energy Stored

U = ½ L I²

📘 LR Circuit

Time constant:

τ = L / R

Current grows/decays exponentially.

🔥 PYQs (Important)

Q1: Moving rod EMF?
Ans: E = Blv
Q2: Time constant?
Ans: τ = L/R
Q3: Energy in inductor?
Ans: ½ L I²

🧠 Tricks

❌ Common Mistakes

🧠 Quiz

Time: 60