🧲 Class 10 Science — Magnetic Effects of Electric Current Original Visual Revision Notes
Aligned with the Class 10 Science syllabus. Independently created study material. Not affiliated with or endorsed by NCERT.
Real-world connection: Think of a magnetic field like an invisible force bubble around your fridge magnet. When you bring a paperclip close to it, the paperclip feels a pull — that is the magnetic force acting through the field. In this lesson you will see how electric current creates its own magnetic field (just like the Earth does!), and how that principle drives every electric motor and generator around you.
🧲 Topic 1: What Is a Magnetic Field?
A magnet pulls iron things toward it.
The area around a magnet is the magnetic field.
We cannot see the field with our eyes.
A compass needle shows the field direction.
The field is strongest near the poles.
➰ Topic 2: Magnetic Field Lines
Field lines show the path of the field.
Lines go from north to south pole outside.
Lines go from south to north inside the magnet.
Two lines never cross each other.
Lines close together mean a strong field.
⚡ Topic 3: Magnetic Field from a Straight Wire
Current in a wire makes a magnetic field.
The field forms circles around the wire.
Use the right-hand rule to find direction.
More current makes a stronger field.
Far from the wire, the field is weaker.
🔄 Topic 4: Field from a Circular Loop
A circular wire with current makes a field.
Field lines look straight at the center.
More turns make the field stronger.
The field acts like a small bar magnet.
Each loop adds to the total field.
🧲 Topic 5: What Is a Solenoid?
A solenoid is a coil of many loops.
It acts like a bar magnet when current flows.
One end becomes north, the other south.
The field inside is strong and uniform.
An iron core makes it an electromagnet.
💪 Topic 6: Force on a Current-Carrying Wire
A wire with current feels a force in a field.
Fleming's left-hand rule gives the direction.
Thumb shows force, index shows field direction.
Middle finger shows current direction.
No force if wire is parallel to the field.
⚙️ Topic 7: Electric Motor
A motor changes electricity into movement.
A coil spins in a magnetic field.
A split ring reverses current each half turn.
This split ring is called a commutator.
Motors are in fans, mixers, and cars.
💡 Topic 8: Electromagnetic Induction
Moving a magnet near a coil makes current.
This is called electromagnetic induction.
Faraday discovered this important effect.
Faster movement makes more current.
More coil turns also give more current.
🔌 Topic 9: Electric Generator and DC vs AC
A generator changes movement into electricity.
AC changes direction again and again.
DC flows in only one direction always.
AC generators use slip rings to work.
DC generators use a split ring commutator.
🏠 Topic 10: Home Electric Circuits
Homes get AC at 220 volts in India.
The live wire carries the current in.
The neutral wire completes the path back.
The earth wire keeps us safe from shocks.
A short circuit happens when wires touch.
🎨 Section 2 — Easy Illustrations
Diagram 1: Field lines around a bar magnet
Diagram 2: Magnetic field around a straight current-carrying wire
Diagram 3: Parts of a simple electric motor
Diagram 4: Moving a magnet into a coil makes current
Diagram 5: Three wires in home electric supply
✏️ Section 3 — Worked Examples
📝 Example 1: Find the Force Direction
A wire carries current to the east. The field points down. Find the force direction.
1
Use Fleming's left-hand rule.
2
Point index finger down for field.
3
Point middle finger east for current.
4
Thumb points to the south direction.
Answer: The force is toward the south.
📝 Example 2: Motor or Generator?
A machine spins a coil to make current. What is it?
1
A motor uses current to make movement.
2
A generator uses movement to make current.
3
This machine spins a coil to get current.
Answer: This is an electric generator.
📝 Example 3: Why Is the Earth Wire Needed?
A metal fridge has a wire fault. What keeps you safe?
1
The live wire may touch the metal body.
2
Current will flow through the metal case.
3
The earth wire sends current to the ground.
4
The fuse blows and cuts off the supply.
Answer: The earth wire saves you from electric shock.
📋 Section 4 — Cheat Sheet
Word
Meaning
Magnetic field
The area around a magnet where force acts.
Field lines
Lines that show the path of a field.
Compass
A small magnet that points north and south.
Solenoid
A coil of wire that acts like a magnet.
Electromagnet
A solenoid with an iron core inside it.
Motor
Changes electric current into spinning motion.
Generator
Changes spinning motion into electric current.
Induction
Making current by moving a magnet near wire.
AC
Current that changes direction again and again.
DC
Current that flows in one direction only.
Fuse
A safety wire that melts if current is too high.
Short circuit
Live wire touches neutral wire directly.
🏠 Section 5 — Take-Home Handout
Part A: Fill in the Blanks
1. The area around a magnet is called the ________.
2. A coil of many loops is called a ________.
3. A motor changes current into ________.
4. Moving a magnet near a coil makes ________.
5. The green wire in a plug is the ________ wire.
Part B: True or False
1. Field lines can cross each other. ________
2. A solenoid acts like a bar magnet. ________
3. AC flows in one direction only. ________
4. The earth wire keeps us safe from shocks. ________
5. A generator makes current from movement. ________
Part C: Solve
1. Name the three wires in a home plug.
2. What is the difference between a motor and a generator?
Part D: Match the Columns
Column A
Column B
1. Motor
a. Makes current from motion
2. Generator
b. Changes current to motion
3. Fuse
c. Changes direction again and again
4. AC
d. Melts when current is too high
Part E: Draw and Label
Draw a simple electric motor. Show the coil, magnet, split ring, and brushes.
✅ Detailed Solutions – Section 5 Handout
Part A: Fill in the Blanks
1
The area around a magnet is called the magnetic field.
2
A coil of many loops is called a solenoid.
3
A motor changes current into motion (rotation).
4
Moving a magnet near a coil makes electric current (electromagnetic induction).
5
The green wire in a plug is the earth wire.
Part B: True or False
1
False. Magnetic field lines never cross each other — they always stay separate.
2
True. A solenoid behaves like a bar magnet, with a North and a South pole.
3
False. AC (Alternating Current) constantly changes direction — that is what makes it different from DC.
4
True. The earth wire provides a safe path for leaked current, preventing electric shocks.
5
True. A generator converts mechanical movement (rotation) into electric current by electromagnetic induction.
Part C: Answers
Q1 — Name the three wires in a home plug.
1
Live wire (brown/red) — carries current at high voltage to the appliance.
2
Neutral wire (blue/black) — returns current back to the supply.
3
Earth wire (green/yellow) — safety wire; carries fault current to earth.
Answer: Live, Neutral, Earth.
Q2 — Difference between a motor and a generator.
1
Motor: takes in electric current → produces motion (current-to-motion).
2
Generator: takes in motion → produces electric current (motion-to-current).
Answer: A motor converts electricity into rotation; a generator converts rotation into electricity — they are opposites of each other.
Part D: Match the Columns
1
Motor → b. Changes current to motion
2
Generator → a. Makes current from motion
3
Fuse → d. Melts when current is too high
4
AC → c. Changes direction again and again
Part E: Electric Motor Diagram Description
1
Draw a rectangular coil (ABCD) between two magnets — N pole on the left, S pole on the right.
2
Attach the two ends of the coil to two half-ring conductors — these form the split ring commutator.
3
Press two carbon brushes against the split ring; connect the brushes to the battery.
4
Label: Battery → Brushes → Split ring → Coil → Magnetic field (N-S poles).
Current in the coil in the magnetic field experiences a force (Fleming's Left-Hand Rule), making the coil rotate. The split ring reverses current direction each half-turn so the coil keeps spinning the same way.