What is Electromagnetic Induction? Simple Meaning with Example
Physics · Electromagnetic Induction · NEET
Electromagnetic induction means a changing magnetic field makes an electric current in a wire, without any battery. When you move a magnet in or out of a coil, the galvanometer needle moves — that current is "induced." Memory hook: no change, no current. The magnet must be moving; a still magnet does nothing.
Pushing the magnet toward the coil changes the magnetic flux through it, so the galvanometer G deflects. Hold the magnet still and the current falls to zero — induction needs a change.
Your doubts, answered
Does a magnet sitting still near a coil make current?
No. A still magnet gives a steady magnetic field, and a steady field makes zero induced current. In Faraday's experiment the galvanometer shows a reading only while the magnet is moving in or out. The moment it stops, the needle returns to zero. The rule to remember: current comes from a CHANGE in the field, not from the field itself.
What actually causes electromagnetic induction, in plain words?
A change in the magnetic 'amount' passing through the coil (called magnetic flux). You can change it by moving a magnet, moving the coil, or changing a nearby current. As long as that amount is changing with time, an emf (voltage) is induced and current flows. When the change stops, induction stops.
How is 'electromagnetism' different from 'electromagnetic induction'?
Electromagnetism (Oersted, Ampere) is the forward effect: a moving charge or current PRODUCES a magnetic field. Electromagnetic induction (Faraday, Henry) is the reverse effect: a CHANGING magnetic field PRODUCES a current. NEET loves this pairing — current makes field vs changing field makes current.
Why does the current reverse when I pull the magnet back out?
Because the field through the coil now decreases instead of increases, so the change is in the opposite direction. The induced current always opposes the change (Lenz's law), so approaching and leaving give opposite current directions. That is why the galvanometer deflects one way going in and the other way coming out.
Do I need a battery to get induced current?
No. That is the whole point of induction — the coil has no cell in it, yet current flows. The energy comes from the work you do moving the magnet (or from whatever changes the field), not from a battery. This is exactly how a generator makes electricity.
⚠️ The NEET trap ✗ A strong magnet held close to a coil keeps a steady current flowing in it. ✓ A steady (unchanging) magnetic field gives zero induced current, no matter how strong. Current appears only while the flux is changing. 🧠 NTA tests 'change', not 'strength'. Big field but not moving = 0 emf.
Real NEET questions
NEET 2024
A strong bar magnet is moving towards solenoid-2 from solenoid-1 (N pole facing right). The directions of induced current in solenoid-1 and solenoid-2 respectively are:
A · BA and CD
B · AB and CD
C · BA and DC
D · AB and DC ✓
Solution: This is the defining EMI demonstration: relative motion of a magnet makes current, and its direction follows Lenz's law (oppose the change). Step 1 — Solenoid-1: the magnet is moving AWAY from it, so the flux through solenoid-1 is decreasing. It induces current to oppose the decrease (to pull the magnet back), giving direction AB. Step 2 — Solenoid-2: the magnet is approaching it, so flux is increasing. It opposes by showing a like (N) pole to the incoming N pole to push it away, giving direction DC. Answer: AB and DC (D). Takeaway: no motion would mean no current in either coil.
NEET 2019 (Odisha)
The variation of EMF with time for four types of generators are shown in the figures. Which amongst them can be called AC?
A · (a) and (d)
B · (a), (b), (c) and (d) ✓
C · (a) and (b)
D · only (a)
Solution: An induced emf is 'alternating current' (AC) if it is periodic and reverses its polarity (changes sign) each cycle. Step 1 — the exact shape does NOT matter: sine, triangle, sawtooth and square all count. Step 2 — check each graph: all four cross the time axis and flip sign periodically. Step 3 — therefore all four, (a),(b),(c),(d), are AC. Answer: B. This connects to induction because a generator uses a changing flux to induce this reversing emf.
Solved Electromagnetic Induction NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Michael Faraday and, independently, Joseph Henry, around 1831. NCERT credits both, which is why the topic is called the Faraday and Henry experiments.
What is the one-line definition for NEET?
Electromagnetic induction is the production of an emf (and current) in a conductor whenever the magnetic flux linked with it changes. Change of flux is the key phrase.
What is a real-life example of electromagnetic induction?
An AC generator (and the dynamo on a cycle). A coil spins in a magnetic field, its flux keeps changing, and that induces the electricity we use. Transformers and induction stoves also use it.
Is induced current the same as normal battery current?
The current itself is ordinary electric current. What is different is its source — it comes from a changing magnetic field, not from a chemical cell, and it stops the instant the change stops.
Which chapter and class is this in?
Class 12 Physics, Chapter 6, Electromagnetic Induction. It is a high-yield NEET chapter that also feeds into Alternating Current.
