Electromagnetic Induction for NEET 2025: Faraday’s Law, Lenz’s Law & Most Expected Questions

Electromagnetic Induction (EMI) is one of the most conceptual and visually intuitive chapters in NEET Physics. Based on the interaction between electricity and magnetism, it’s known for predictable questions that test your grasp of direction of induced current, change in magnetic flux, and the use of simple formulas.

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Why It Matters for NEET:

Appears almost every year with 1–2 questions
Questions are typically from Faraday’s Law, Lenz’s Law, or induced EMF calculations
Requires more understanding than memorization
High scoring once concept is clear

In this blog, we’ll cover:

Faraday’s Laws of Induction
Lenz’s Law and direction of current
Induced EMF formulas
Application-focused MCQs based on NEET trends

NEET Chapter Weightage & Trends

Electromagnetic Induction contributes around 4 marks in the Physics section of NEET, almost every year.

What NEET focuses on:

Faraday’s Law: What causes EMF, and how to calculate it
Lenz’s Law: Direction of induced current (especially in coils and loops)
Induced EMF: Especially in rods, loops, and moving conductors
Self and Mutual Induction: Concept-based theory questions

NEET 2020–2024 Trends:

NEET 2023: Question on induced current direction using Lenz’s law
NEET 2022: Application of EMF = Blv in a rod moving in magnetic field
NEET 2021: Conceptual question on energy stored in inductors
NEET 2020: EMF calculation from changing magnetic flux

Almost every question can be solved using a formula + direction rule if understood well.

Previous year NEET papers reveal key trends.

Faraday’s Law of Electromagnetic Induction

Faraday’s Laws explain how EMF (electromotive force) is induced when there is a change in magnetic environment around a conductor.

Faraday’s First Law

Whenever there is a change in magnetic flux linked with a coil, an EMF is induced in the coil.

The EMF can produce current if the circuit is closed. This is the basic principle behind electricity generation.

Faraday’s Second Law

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

$boldsymbol{text{EMF} = -frac{dPhi}{dt}}$
Where:

$boldsymbol{Phi = B cdot A cdot cos theta}$
$boldsymbol{B}$ = Magnetic field

$boldsymbol{A}$ = Area vector

Negative sign indicates Lenz’s Law (the induced EMF opposes the change)

NEET Applications of Faraday’s Law

A magnet moving into or out of a coil
Loop rotating in a magnetic field (AC generation principle)
A rod sliding on rails in a perpendicular magnetic field
Finding induced EMF over time, rate of change of flux, or net charge flow

Mock tests boost speed and accuracy.

Lenz’s Law: Direction of Induced Current

What is Lenz’s Law?

The induced current (and EMF) always flows in a direction that opposes the change in magnetic flux that produced it.

This is nature’s way of conserving energy. If the induced current aided the cause, it would lead to energy gain from nowhere, violating the law of conservation of energy.

This law explains the negative sign in Faraday’s second law.

Right-Hand Thumb Rule / Fleming’s Right-Hand Rule

Used to determine the direction of induced current:

Fleming’s Right-Hand Rule:
- Thumb → Direction of motion (conductor)
- Forefinger → Magnetic field direction (B)
- Middle finger → Direction of induced current (I)

This is particularly useful in EMF = Blv type questions.

NEET Focus Areas

Here’s how NEET commonly tests Lenz’s Law:

Pulling a coil from/into a magnetic field → Predict induced current direction
Closed loop near a moving magnet → Direction of flow based on opposing field
Rod sliding on conducting rails → Visualize induced current direction
MCQs involving increasing/decreasing flux → Conceptual elimination

Remember: induced current always “resists” the change — whether flux increases or decreases.

Self-Induction & Mutual Induction

Understanding inductance is key to mastering EMI concepts in NEET.

Self-Inductance (L)

When the current in a coil changes, the coil opposes the change by inducing an EMF in itself. This is called self-induction.

$boldsymbol{text{EMF} = -L frac{di}{dt}}$

$boldsymbol{L}$ = self-inductance
Negative sign: shows opposition to change (Lenz’s Law)
Unit: Henry (H)
Higher $boldsymbol{L}$ = greater opposition to current change

Mutual Inductance (M)

Occurs when a changing current in one coil induces EMF in a nearby coil.

$boldsymbol{text{EMF} = -M frac{di}{dt}}$

M = mutual inductance
Depends on proximity, orientation, and turns of the coils

NEET Angle:

Questions may compare self vs mutual inductance
Use dimensional analysis to find units:
- $boldsymbol{[L] = [M] = text{Henry} = frac{V cdot s}{A}}$
Circuit-based MCQs may involve induced EMF in coupled coils

Induced EMF in Rods & Loops

This section is frequently asked in NEET as it involves visual reasoning + formula usage.

Moving Rod in Magnetic Field

When a conducting rod of length lll moves with velocity v perpendicular to magnetic field B:

$boldsymbol{text{EMF} = B cdot l cdot v}$

Where:

$boldsymbol{B}$ = Magnetic field strength (Tesla)
$boldsymbol{l}$ = Length of the rod
$boldsymbol{v}$ = Velocity (perpendicular to magnetic field)

Direction of current: determined using Fleming’s Right-Hand Rule

Other Important Setups

Faraday Disc: Rotating metallic disc in magnetic field → radial EMF
Loop entering/exiting magnetic field: Induced current opposes flux change
Rail + Rod system: Frequently used for NEET visuals

NEET often uses illustrations with rods sliding on rails, magnets moving near coils, or loops entering field zones to test understanding of direction + formula.

Important Formulas to Remember

Concept	Formula
Faraday’s Law	$boldsymbol{text{EMF} = -frac{dPhi}{dt}}$
Magnetic Flux	$boldsymbol{Phi = B cdot A cdot cos theta}$
EMF in Moving Rod	$boldsymbol{text{EMF} = B cdot l cdot v}$
Self-Induced EMF	$boldsymbol{text{EMF} = -L cdot frac{di}{dt}}$
Mutual Induction	$boldsymbol{text{EMF} = -M cdot frac{di}{dt}}$
Inductance Unit	$boldsymbol{1,text{H} = 1,frac{V cdot s}{A}}$

Tip: Create a flashcard with these equations and practice units for dimensional analysis questions.

NEET PYQs: Solved Examples

Let’s review some typical NEET-style EMI questions with solutions.

Q1. A conducting rod of length 0.5 m moves at 4 m/s perpendicular to a magnetic field of 0.2 T. Find the induced EMF.

Solution:

$boldsymbol{text{EMF} = B cdot l cdot v = 0.2 cdot 0.5 cdot 4 = 0.4,text{V}}$

Answer: 0.4 V

Q2. The current in a coil changes from 0 to 5 A in 0.1 s. If the self-inductance is 2 H, find the induced EMF.

Solution:

$boldsymbol{text{EMF} = -L frac{di}{dt} = -2 cdot frac{5}{0.1} = -100,text{V}}$

Answer: 100 V (magnitude)

Q3. A circular loop is moving out of a uniform magnetic field region. What is the direction of the induced current?

Solution:
According to Lenz’s Law, current opposes the decrease in flux → produces field into the page. So, the current is clockwise.

Answer: Clockwise

Q4. What is the unit of inductance?

Solution:
From $boldsymbol{text{EMF} = -L frac{di}{dt}}$ ,

$boldsymbol{L = frac{V cdot s}{A}}$

Answer: $boldsymbol{1, text{Henry (H)} = frac{V cdot s}{A}}$

Revision Tips for EMI

Here’s how to prepare efficiently for this chapter:

✔️ Draw diagrams: Practice coil and rod scenarios — direction of motion, field, and induced current
✔️ Memorize formulas: Especially Faraday’s Law, EMF in rods, and inductance equations
✔️ Understand signs: The negative sign in EMF is key (Lenz’s Law)
✔️ Use visual aids: Watch videos or animations for Lenz’s Law — improves recall during exam
✔️ Solve PYQs: Focus on questions from NEET 2016–2024 to see repeating formats

FAQs on Electromagnetic Induction for NEET

Q: Is Electromagnetic Induction (EMI) a difficult chapter for NEET?

A: Not at all. EMI is more about understanding the core concepts than solving lengthy calculations. Once you grasp Lenz’s Law and the idea of changing magnetic flux, most NEET questions become straightforward.

Q: What is the most important concept in EMI for NEET?

A: The high-yield topics are:

Faraday’s Law of Induction
Lenz’s Law (direction of current)
Induced EMF in moving rods → EMF = B × l × v
Self and mutual induction formulas

Mastering these ensures you’re prepared for almost any EMI-based MCQ.

Q: How can I revise EMI quickly before NEET?

A: Here’s a smart revision plan:

Use flashcards for formulas (Faraday, Lenz, Blv, etc.)
Revise 2–3 Lenz’s Law examples visually (from PYQs or YouTube animations)
Solve 5–10 NEET previous year questions for pattern recognition
Focus on conceptual elimination strategies for direction-based MCQs

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Conclusion

Electromagnetic Induction is one of those NEET Physics chapters that’s concept-heavy but highly predictable. With a little clarity in logic and formula usage, it can easily become a high-scoring topic.

Even better — EMI often tests your understanding, not your speed, making it a perfect target for accuracy-focused aspirants.