Physics in ECET 2026 often includes Magnetism and Electromagnetic Induction questions. These are easy to score if formulas and concepts are revised properly.
📘 Concept Notes
🌐 Magnetism
- Magnetism is the force of attraction/repulsion due to moving charges (currents).
- Magnetic field (B): Region around a magnet where its force is experienced.
Formula:
Where:
= magnetic force,
= charge,
= velocity of charge,
= angle between velocity & magnetic field.
Ampere’s Law:
Magnetic field due to a long straight conductor:
Magnetic field inside a solenoid:
where 
is number of turns per unit length.
⚡ Electromagnetic Induction (EMI)
- Discovered by Faraday: A changing magnetic flux induces EMF.
Faraday’s Law:
Magnetic Flux:
Lenz’s Law:
Induced current direction opposes the cause producing it.
Self Inductance (L):
Mutual Inductance (M):
Energy stored in an inductor:
📐 Example
- A solenoid has
turns, length 
, current 
.
- A coil of area
in magnetic field 
, flux when perpendicular (
):
🔟 10 Expected MCQs – ECET 2026
Q1. The SI unit of magnetic flux is:
A) Tesla
B) Weber
C) Henry
D) Joule
Q2. Magnetic field due to long straight conductor is proportional to:
A) Current
B) Distance
C) 
D) Both A and C
Q3. The magnetic field inside a solenoid is given by:
A) 
B)
C) 
D) 
Q4. Faraday’s law states:
A) Current produces magnetism
B) Change in flux induces EMF
C) Force acts on moving charges
D) None
Q5. Lenz’s law is based on:
A) Law of inertia
B) Conservation of charge
C) Conservation of energy
D) Conservation of momentum
Q6. Unit of self-inductance is:
A) Tesla
B) Weber
C) Henry
D) Ampere
Q7. Energy stored in an inductor is:
A) 
B) 
C) 
D) None
Q8. The direction of induced current is given by:
A) Ampere’s law
B) Faraday’s law
C) Lenz’s law
D) Fleming’s right-hand rule
Q9. A coil of 500 turns changes flux by 
in 0.5 sec. Induced EMF?
A) 10 V
B) 50 V
C) 100 V
D) 200 V
Q10. Fleming’s right-hand rule gives:
A) Direction of force
B) Direction of current
C) Direction of induced EMF
D) Direction of field
✅ Answer Key
| Q.No | Answer |
|---|---|
| Q1 | B |
| Q2 | D |
| Q3 | B |
| Q4 | B |
| Q5 | C |
| Q6 | C |
| Q7 | A |
| Q8 | C |
| Q9 | B |
| Q10 | C |
🧠 Explanations
- Q1 → B: Flux unit = Weber (Wb).
- Q2 → D:
⇒ proportional to I and . - Q3 → B: Solenoid field =
. - Q4 → B: Faraday’s law – induced EMF ∝ change in flux.
- Q5 → C: Lenz’s law is based on energy conservation.
- Q6 → C: Unit of inductance is Henry.
- Q7 → A: Energy = .
- Q8 → C: Lenz’s law gives induced current direction.
- Q9 → B:
. - Q10 → C: Fleming’s right-hand rule = induced EMF direction.
🎯 Why Practice Matters
- Magnetism & EMI carry 2–3 direct questions every ECET exam.
- Questions are formula-based and conceptual.
- Solving MCQs ensures accuracy and confidence.
