1. What is Electromagnetic Induction?

The production of induced EMF (electromotive force) in a conductor due to change in magnetic flux linked with it.

GenZ Example

When you move a magnet near a coil and a bulb glows briefly — that’s EMI.

2. Important AAI ATC Focused Concepts

3. Faraday’s First Law of EMI

Whenever magnetic flux linked with a closed circuit changes, an EMF is induced in the circuit.

PYQ Type: Concept theory MCQ

4. Faraday’s Second Law

The magnitude of induced EMF is proportional to the rate of change of magnetic flux.

\( e = -\frac{d\Phi}{dt} \)

Where:

Φ: Magnetic flux (Wb = T·m²)

PYQ Type: Formula MCQ

5. Lenz’s Law

The direction of induced current is such that it opposes the cause producing it.

GenZ Example

Moving a magnet towards a coil — induced current creates a repulsive magnetic field.

PYQ Type: Direction concept MCQ

6. Induced EMF in a Moving Conductor

The EMF induced when a conductor moves in a magnetic field.

\( e = B l v \sin\theta \)

Where:

B: Magnetic field (T)
l: Length (m)
v: Velocity (m/s)
θ: Angle between B and v

PYQ Type: Possible numerical MCQ

7. Self Inductance (L)

When current in a coil changes, it induces EMF in itself.

\( e = -L \frac{di}{dt} \)

Unit: Henry (H)

PYQ Type: Unit match MCQ

8. Mutual Inductance (M)

When a change in current in one coil induces EMF in another nearby coil.

\( e = -M \frac{di}{dt} \)

Unit: Henry (H)

9. AAI ATC PYQ Analysis (2021–2023)

2021 Shift 2: Lenz’s law direction MCQ

2022 Shift 3: Unit of self-inductance (Henry)

2023 Feb Shift 1: Faraday’s law formula MCQ

10. EMI Formula Quick Revision

Formula	Meaning
\( e = -\frac{d\Phi}{dt} \)	Faraday’s 2nd law
\( e = B l v \sin\theta \)	EMF in moving conductor
\( e = -L \frac{di}{dt} \)	Self inductance
\( e = -M \frac{di}{dt} \)	Mutual inductance

11. Quick Concept Recap

Concept	GenZ Example
Moving magnet near coil glows bulb	Induced EMF
Induced current opposes cause	Lenz’s Law
Faster flux change = greater EMF	Shaking magnet harder
Unit of inductance is Henry	Symbol H like Tesla for field

12. Final AAI ATC Takeaway

Focus Areas:

1–2 MCQs per shift
Faraday’s 2nd law formula
Lenz’s law statement
Unit of inductance (Henry)
EMF in moving conductor formula

13. 10-Question AAI ATC-Style MCQ Mock Test — EMI

Q1. Unit of self-inductance is:
a) Tesla
b) Henry
c) Weber
d) Ampere
Ans: b

Q2. Formula for EMF induced in a moving conductor is:
a) B l v
b) B² l
c) I R
d) q v B
Ans: a

Q3. Faraday’s second law states that EMF is proportional to:
a) Flux
b) Rate of change of flux
c) Magnetic field only
d) None
Ans: b

Q4. Lenz’s law is based on:
a) Conservation of charge
b) Conservation of energy
c) Conservation of momentum
d) Ohm’s law
Ans: b

Q5. Induced current direction opposes:
a) Magnetic flux
b) Cause producing it
c) Coil shape
d) None
Ans: b

Q6. Unit of magnetic flux is:
a) Tesla
b) Weber
c) Henry
d) Volt
Ans: b

Q7. EMF induced in a coil depends on:
a) Number of turns
b) Rate of flux change
c) Both
d) None
Ans: c

Q8. In which condition is EMF zero in a moving conductor?
a) θ = 90°
b) θ = 0°
c) θ = 45°
d) θ = 180°
Ans: b

Q9. Which of these devices uses EMI?
a) Transformer
b) Voltmeter
c) Ammeter
d) Resistance wire
Ans: a

Q10. SI unit of mutual inductance is:
a) Tesla
b) Henry
c) Weber
d) Ampere
Ans: b