Science · Class 10
Magnetic Effects of Electric Current
Magnetic field, Fleming's rules, electric motor, and generator.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Electric current produces magnetic fields; moving magnets can induce current. Covers field patterns, Fleming's rules, electric motor, generator, and domestic AC — links electricity and magnetism.
Magnetic Field due to Current
Straight wire
B ∝ I/r (concentric circles — right-hand thumb rule)
Solenoid
B ∝ nI (uniform field inside)
Force on conductor
F = BIL sin θ
Motor & Generator
- Motor: electrical → mechanical (Fleming's left-hand rule)
- Generator: mechanical → electrical (electromagnetic induction)
- Fleming's right-hand rule: induced current direction
Domestic AC
- AC reverses direction periodically
- Frequency in India: 50 Hz
- Live wire alternates potential; neutral at ~0 V
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Force on wire
I=5A, B=0.2T, L=0.4m, θ=90°. Find F.
- 1F = BIL sin 90° = 0.2×5×0.4
Answer
0.4 N
Right-hand rule
Current north in wire below compass. Needle deflects?
- 1Thumb along current, fingers curl = B direction
- 2Field circles wire
- 3Compass aligns with resultant field
Answer
Deflects east-west depending on position
Key Points to Remember
- ✓ Electromagnet: soft iron core in solenoid
- ✓ Earth wire prevents electric shock
- ✓ Short circuit: very high current, fuse melts
Exam Tips
- • Use Fleming's rules with clear diagram
- • Distinguish motor vs generator principle
- • Draw field lines for solenoid
Practice MCQs — Magnetic Effects of Electric Current
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Unit of magnetic field B: