What is the function of the earth wire in household wiring?

The earth wire (green/yellow insulation) connects the metallic body of an appliance to a metal plate buried deep in the earth. If a fault causes the live wire to touch the metal casing, current flows through the earth wire (a low-resistance path) to the ground instead of through the user's body. This large fault current blows the fuse or trips the MCB, disconnecting the circuit and preventing electric shock.

What is electromagnetic induction and Faraday's law?

Electromagnetic induction is the phenomenon of producing an induced EMF (and hence current) in a coil whenever the magnetic flux linked with it changes. Faraday's law states that the magnitude of the induced EMF is directly proportional to the rate of change of magnetic flux through the circuit. This can happen by moving a magnet towards/away from a coil, or by rotating a coil in a magnetic field.

Magnetic Effects of Electric Current Exercise Solutions | KalviGavani

Q: What is the difference between an electric motor and an electric generator?

An electric motor converts electrical energy into mechanical energy; it works on the principle that a current-carrying conductor experiences a force in a magnetic field (Fleming's left-hand rule). An electric generator converts mechanical energy into electrical energy; it works on the principle of electromagnetic induction — relative motion between a coil and a magnet induces an EMF (Fleming's right-hand rule). The motor takes in current; the generator produces current.

Exercise Solutions Available

Step-by-step answers for all textbook questions in this chapter

View Solutions →

How to Use This Page

1. Attempt every question yourself first — read the question, write your answer, then compare with the solution here. 2. Master both Fleming's rules — left-hand rule (motor/force) and right-hand rule (generator/induction). They appear in every board exam. 3. Practise diagram descriptions — the motor, generator, domestic wiring, and magnetic field patterns are high-yield diagram questions. Visualise each one. 4. Focus on the Key Concepts section before solving — it gives you the conceptual foundation to answer any variation the board sets. 5. Check the Exam Checklist at the end — if you can tick every item, you are exam-ready.

Key Concepts (Quick Recap)

Magnetic Field and Field Lines

A magnetic field is the region around a magnet where its magnetic influence (force) can be detected.
Magnetic field lines are imaginary curves along which a free north pole would tend to move.
Properties of magnetic field lines:
They emerge from the North pole and enter the South pole outside the magnet.
Inside the magnet, they run from South to North — forming closed continuous loops.
They never intersect each other (a point can have only one direction of the field).
Closer spacing = stronger field; wider spacing = weaker field.
The tangent at any point on a field line gives the direction of the magnetic field at that point.

Magnetic Field Due to a Current-Carrying Conductor

Straight wire: Magnetic field lines are concentric circles centred on the wire. Their spacing increases with distance from the wire (field weakens).
Right-hand thumb rule: Grasp the wire with your right hand so the thumb points in the direction of conventional current — the curled fingers show the direction of the magnetic field lines around the wire.
Circular loop: Field lines at the centre are nearly straight (parallel). The direction inside the loop is given by the right-hand thumb rule — curl fingers along the current, thumb gives field direction at the centre. Field is stronger at the centre of the loop.
Solenoid: A long coil of many turns. Inside, the field is uniform (same at all points) and parallel to the axis. Outside, it resembles a bar magnet — field lines emerge from one end (North) and enter the other (South). The strength of the field is proportional to the number of turns per unit length and the current.

Electromagnet vs Permanent Magnet

Feature	Electromagnet	Permanent Magnet
Source of magnetism	Current in a solenoid with soft iron core	Hard steel or alloys (Alnico)
Strength	Can be varied by changing current	Fixed
Poles	Can be reversed by reversing current	Fixed N and S
Behaviour when source removed	Loses magnetism (soft iron core)	Retains magnetism
Uses	Cranes, electric bells, loudspeakers	Compasses, fridge magnets

Force on a Current-Carrying Conductor in a Magnetic Field

A conductor carrying current placed in a magnetic field experiences a mechanical force (Ampere's force).
Magnitude: F = BIL (B = magnetic field strength, I = current, L = length of conductor in the field).
Direction: given by Fleming's left-hand rule.
The force is maximum when the conductor is perpendicular to the field; zero when parallel.
The displacement (deflection) of the conductor increases when: (a) current increases, (b) magnetic field strength increases.

Fleming's Left-Hand Rule (Motor Rule)

Stretch the thumb, index finger, and middle finger of your left hand at right angles to each other:

Index finger → direction of Magnetic field (B), North to South.
Middle finger → direction of Current (I), conventional current.
Thumb → direction of Force/Motion on the conductor.

Electric Motor

Principle: A current-carrying conductor placed in a magnetic field experiences a force. A coil carrying current in a magnetic field rotates due to equal and opposite forces on its two sides.
Construction: Rectangular coil ABCD between the N and S poles of a permanent magnet. The coil is connected to a source through brushes B1, B2 and a split-ring commutator (two half-rings R1 and R2).

Working

Current enters via brush B1 → commutator ring R1 → side AB → side BC → side CD → commutator ring R2 → brush B2.
By Fleming's left-hand rule: Force on AB is downward, force on CD is upward → couple rotates the coil anticlockwise (as seen from the commutator end).
After half rotation, the commutator halves swap brushes — current in AB reverses direction — forces reverse — coil continues rotating in the same direction.
Split-ring commutator: Reverses the direction of current through the coil every half rotation, ensuring unidirectional rotation.
Energy conversion: Electrical energy → Mechanical energy.

Electromagnetic Induction

The phenomenon of producing an induced EMF (and hence induced current) in a circuit by changing the magnetic flux linked with it.
Faraday's law: The magnitude of induced EMF is directly proportional to the rate of change of magnetic flux.
Induced current can be produced by: (a) moving a magnet towards or away from a coil, (b) moving a coil towards or away from a magnet, (c) rotating a coil in a magnetic field, (d) changing current in a nearby coil.
Fleming's right-hand rule (Generator rule): Stretch the thumb, index finger, and middle finger of your right hand at right angles:
Thumb → direction of Motion of the conductor.
Index finger → direction of Magnetic field (B).
Middle finger → direction of Induced current (I).

Electric Generator

Principle: Electromagnetic induction — when a coil rotates in a magnetic field, the changing magnetic flux induces an alternating EMF.
AC Generator: Uses slip rings (two continuous rings) — each end of the coil is connected to a separate slip ring. Current in the external circuit alternates direction every half cycle.
DC Generator: Uses a split-ring commutator — connections reverse every half rotation, so current in the external circuit flows in one direction only (though it pulsates).
Generator diagram: Rectangular coil rotated between N and S poles of a magnet. Slip rings (AC) or commutator (DC) connect coil to external circuit via brushes. As coil rotates, the flux through it changes continuously, inducing EMF. Induced current is maximum when the coil is perpendicular to the field and zero when parallel.
Energy conversion: Mechanical energy → Electrical energy.

Domestic Electric Circuits

Three-wire system:
Live wire (Phase): Red or brown insulation; carries current at 220 V (in India); connected to the meter and switchboard.
Neutral wire: Black or blue insulation; at approximately 0 V; completes the circuit by providing a return path.
Earth wire: Green or green/yellow insulation; connects metallic bodies of appliances to the earth (ground); safety wire.

Fuse: A short piece of wire made of a material with a low melting point (e.g., tin-lead alloy). Placed in the live wire. When current exceeds its rated value, the fuse wire melts and breaks the circuit, protecting appliances and preventing fire. Fuses are rated in amperes (e.g., 5 A, 15 A).

MCB (Miniature Circuit Breaker): Modern replacement for fuses. Automatically trips (switches off) when current exceeds the rated value. Can be reset manually — no replacement needed.

Short circuit: When live and neutral wires come into direct contact (insulation failure), resistance drops to near zero, and current increases heavily (I = V/R, R ≈ 0). This can cause fire.

Overloading: When too many appliances are connected to a single circuit, the total current drawn exceeds the safe rating of the wiring. Causes overheating, insulation damage, and fire risk.

Intext Questions

Page 224

Q1. Why does a compass needle get deflected when brought near a bar magnet?

Answer

A compass needle is itself a small bar magnet free to rotate on a pivot. When it is brought near a bar magnet, the magnetic field of the bar magnet exerts forces on both poles of the compass needle. The north pole of the compass is attracted towards the south pole of the bar magnet and repelled by its north pole. These forces create a torque that rotates (deflects) the compass needle until it aligns along the direction of the bar magnet's field at that point. The deflection is direct evidence that a magnetic field exists around the bar magnet.

Page 228

Q1. Draw magnetic field lines around a bar magnet.

Answer

Since we are describing the diagram in text:

Bar magnet field-line diagram: Place a bar magnet with N on the left and S on the right on a sheet of paper. Sprinkle iron filings or use a compass to trace the field lines. The pattern shows:

Lines emerge from the North pole, curve outward through the surrounding space, and enter the South pole.
Inside the magnet, the lines go from South to North, forming closed loops.
The lines are crowded near the poles (strong field) and spread apart far from the magnet (weak field).
No two field lines cross each other.
The lines form characteristic symmetrical loops on both sides of the magnet.

Q2. List the properties of magnetic field lines.

Answer

1. Magnetic field lines are closed continuous curves — they have no beginning or end. 2. Outside the magnet, they emerge from the North pole and enter the South pole. Inside the magnet, they go from South to North. 3. No two field lines intersect — at any point, the magnetic field has a unique direction. 4. The closeness of the lines represents the strength of the field — closely spaced = strong field; widely spaced = weak field. 5. The tangent drawn at any point on a field line gives the direction of the magnetic field at that point. 6. They are imaginary lines — a convenient way to represent the field visually.

Page 229

Q1. Why don't two magnetic field lines intersect each other?

Answer

If two magnetic field lines were to intersect at a point, it would mean that at that point the magnetic field has two different directions simultaneously. But the magnetic field at any point in space has a unique direction — a compass needle placed there can point in only one direction. Two directions at one point is physically impossible. Therefore, magnetic field lines can never cross or intersect.

Page 230

Q1. Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand thumb rule to find out the direction of the magnetic field inside and outside the loop.

Answer

Apply the right-hand thumb rule:

Curl the fingers of your right hand in the direction of clockwise current (as seen from above the table).
Your thumb points downward (into the table) — this is the direction of the magnetic field inside the loop.
Outside the loop, the field lines emerge from below the table upward, forming concentric circles around the wire. At points just outside the loop, the field is directed out of the table (upward).

So, inside the loop: field is into the table; outside the loop: field is out of the table.

Page 235

Q1. The magnetic field inside a long straight solenoid carrying current: (a) is zero (b) decreases as we move towards its end (c) increases as we move towards its end (d) is the same at all points

Answer(d) is the same at all points.

A long solenoid produces a uniform magnetic field inside it — the field lines are parallel and equally spaced throughout the interior. This is analogous to the uniform field between the plates of a parallel-plate capacitor. Near the ends the field lines begin to diverge, but for a long solenoid, the interior field is practically the same everywhere.

Page 238

Q1. A positively charged particle (alpha particle) moving towards the west is deflected towards the north by a magnetic field. What is the direction of the magnetic field?

Answer

Using Fleming's left-hand rule:

Current direction (middle finger) = direction of motion of positive charge = West.
Force/deflection direction (thumb) = North.
Magnetic field direction (index finger) must be Upward (vertically up, out of the plane if West is horizontal left and North is forward).

So the magnetic field is directed vertically upward.

Q2. Fleming's left-hand rule.

Answer

(Described in Key Concepts above.)

Stretch the thumb, index finger, and middle finger of the left hand at right angles:

Index finger → direction of magnetic field (B), from North to South.
Middle finger → direction of current (I).
Thumb → direction of force (motion) on the conductor.

This rule helps determine the direction of force on a current-carrying conductor in a magnetic field and is used in understanding the working of electric motors.

Page 240

Q1. What is the principle of an electric motor? State its working.

Answer

Principle: When a current-carrying conductor (or coil) is placed in a magnetic field, it experiences a force. If the conductor is free to move, it does so. In a motor, a rectangular coil carrying current in a magnetic field experiences a torque (couple) due to opposite forces on its two arms, causing it to rotate.

Working of a DC motor:

Motor diagram: Rectangular coil ABCD placed between N (left) and S (right) poles of a permanent magnet. Current enters through brush B1 and commutator half-ring R1, flows through arm AB (left side) from A to B, across BC, down arm CD from C to D, exits through commutator half-ring R2 and brush B2.

Applying Fleming's left-hand rule: Force on AB pushes it downward; force on CD pushes it upward. These two equal and opposite forces form a couple → coil rotates.
After half rotation, the commutator halves swap which brush they contact — current in the coil reverses direction. Now AB is pushed upward and CD is pushed downward. The coil continues rotating in the same direction.
The split-ring commutator is essential: it reverses current direction every half turn so the torque always acts in the same rotational sense.

Energy conversion: Electrical energy → Mechanical (rotational) energy.

Page 242

Q1. What is electromagnetic induction?

Answer

Electromagnetic induction is the phenomenon in which a changing magnetic flux through a circuit induces an EMF (and hence a current) in the circuit. This was discovered by Michael Faraday. The induced EMF exists only as long as the change in magnetic flux continues. Key ways to produce it:

Moving a magnet towards or away from a coil.
Moving a coil towards or away from a magnet.
Rotating a coil in a magnetic field.
Changing the current in a nearby coil (mutual induction).

Q2. Fleming's right-hand rule.

Answer

Stretch the thumb, index finger, and middle finger of the right hand at right angles:

Thumb → direction of motion of the conductor (or relative motion).
Index finger → direction of the magnetic field (B), from North to South.
Middle finger → direction of induced current in the conductor.

This rule is used to determine the direction of induced current in a generator.

Page 245

Q1. Draw a labelled diagram of a domestic electric circuit.

Answer

Domestic wiring diagram description:

The power supply comes from the electric pole through three wires into the house: 1. Live wire (red/brown): Carries 220 V. Enters the house through an electric meter (records energy consumption in kWh), then goes to the main switch/fuse on a distribution board. 2. Neutral wire (black/blue): Returns current to the supply. Also passes through the meter. 3. Earth wire (green/yellow): Connected to a metal plate buried in the ground; does not carry current in normal operation.

From the distribution board, separate circuits branch out:

Each circuit has its own fuse (in the live wire) rated for the circuit's safe current (e.g., 5 A for lighting, 15 A for power appliances).
All appliances are connected in parallel between the live and neutral wires (each gets full 220 V).
All switches are on the live wire — so when switched off, the appliance is disconnected from the high voltage.
The metallic body of each appliance is connected to the earth wire for safety.

Chapter-End Exercise

Q1. Which of the following correctly describes the magnetic field near a long straight current-carrying wire? (a) The field consists of straight lines parallel to the wire. (b) The field consists of straight lines perpendicular to the wire. (c) The field consists of radial lines originating from the wire. (d) The field consists of concentric circles centred on the wire.

Answer(d) The magnetic field near a long straight current-carrying wire consists of concentric circles centred on the wire. Their direction is given by the right-hand thumb rule. The circles are closer together near the wire (stronger field) and spread apart farther away.

Q2. The phenomenon of electromagnetic induction is: (a) the process of charging a body. (b) the process of rotating a coil of an electric motor. (c) producing induced current in a coil due to relative motion between a magnet and the coil. (d) the process of rotating a coil in a magnetic field to produce current.

Answer(c) Electromagnetic induction is the production of an induced EMF (and current) in a coil due to a changing magnetic flux, typically caused by relative motion between the coil and a magnet. Option (d) is incomplete because merely rotating a coil is not sufficient — the rotation must cause a change in flux, and more importantly, option (c) correctly identifies the key idea: relative motion between magnet and coil.

Q3. The device used for producing electric current is called a: (a) generator (b) galvanometer (c) ammeter (d) motor

Answer(a) generator. A generator converts mechanical energy into electrical energy using electromagnetic induction. A galvanometer detects current, an ammeter measures current, and a motor consumes (not produces) current.

Q4. The essential difference between an AC generator and a DC generator is that: (a) AC generator has an electromagnet while a DC generator has a permanent magnet. (b) DC generator will generate a higher voltage. (c) AC generator has slip rings while the DC generator has a commutator (split rings). (d) AC generator has a coil on its armature while the DC generator does not.

Answer(c) The key structural difference is the method of connecting the rotating coil to the external circuit:

AC generator: Uses slip rings (two continuous conducting rings) — each end of the coil connects to one ring. As the coil rotates, the current in the external circuit alternates direction every half cycle.
DC generator: Uses a split-ring commutator (two half-rings) — the connections to the external circuit reverse every half rotation, so the current in the external circuit always flows in the same direction.

Both use permanent magnets (or electromagnets), both have armature coils, and voltage is not inherently different.

Q5. At the time of short circuit, the current in the circuit: (a) reduces substantially (b) does not change (c) increases heavily (d) varies continuously

Answer(c) increases heavily. A short circuit occurs when the live wire and neutral wire come into direct contact (insulation breakdown, faulty wiring). The resistance of the circuit drops to nearly zero. By Ohm's law (I = V/R), when R approaches zero, the current becomes extremely large. This dangerously high current heats the wires, can cause fire, and blows the fuse or trips the MCB.

Q6. State the principle of an electric motor.

Answer

An electric motor works on the principle that a current-carrying conductor placed in a magnetic field experiences a mechanical force. When a rectangular coil carrying current is placed in a magnetic field, the two opposite sides of the coil experience forces in opposite directions, creating a torque (rotational force) that causes the coil to rotate. The direction of force on each side is determined by Fleming's left-hand rule. The motor thus converts electrical energy into mechanical energy.

Q7. State the principle of an electric generator.

Answer

An electric generator works on the principle of electromagnetic induction (Faraday's law). When a coil is rotated in a magnetic field, the magnetic flux through the coil changes continuously. This changing flux induces an alternating EMF in the coil, which drives a current through the external circuit. The direction of the induced current is given by Fleming's right-hand rule. The generator thus converts mechanical energy into electrical energy.

Q8. Name some sources of direct current.

Answer

1. Dry cell (torch cell, zinc-carbon cell) 2. Lead-acid battery (car battery, inverter battery) 3. DC generator (dynamo with split-ring commutator) 4. Solar cell (photovoltaic cell) 5. Button cell (used in watches)

All these sources produce current that flows in one direction only (unidirectional).

Q9. Which sources produce alternating current?

Answer

1. AC generator (alternator) — used in thermal, hydroelectric, and nuclear power stations. 2. Bicycle dynamo (small AC generator). 3. Inverter (converts DC from battery to AC during power cuts).

These sources produce current that reverses direction periodically (50 times per second in India, i.e., 50 Hz frequency).

Q10. Choose the correct option: A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each: (a) two revolutions (b) one revolution (c) half revolution (d) one-quarter revolution

Answer(c) half revolution. As the coil rotates, each side of the coil moves up through the field for one half turn and down through the field for the next half turn. When the motion of a side relative to the field reverses (at each half revolution), the direction of induced current in that side also reverses. Therefore, the current direction changes twice per full revolution — once every half revolution.

Q11. Name two safety measures commonly used in electric circuits and appliances. Explain their working.

1. Electric Fuse:

Answer

A fuse is a short piece of wire made of an alloy (tin-lead) with a low melting point.
It is connected in the live wire of the circuit, before the appliance.
Under normal current, the fuse wire does not melt. When the current exceeds its rated value (due to short circuit or overloading), the fuse wire heats up, melts, and breaks the circuit, stopping the flow of excess current.
This protects the appliance from damage and prevents fire.
Fuses are rated in amperes — a 5 A fuse melts if current exceeds 5 A.

2. Earth Wire (Earthing):

Answer

The earth wire (green/yellow insulation) connects the metallic body of an appliance to a metal plate buried deep in the ground.
In normal operation, no current flows through the earth wire.
If a fault occurs and the live wire touches the metal casing, a large current flows through the earth wire (low-resistance path) to the ground.
This heavy current blows the fuse or trips the MCB, disconnecting the appliance from the supply.
The user touching the appliance is protected from electric shock because the current goes to earth instead of through the human body.

MCB (Miniature Circuit Breaker) is a modern alternative to fuses — it trips automatically on overload and can be reset manually.

Q12. An electric oven of 2 kW power rating is operated in a domestic circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.

GivenPower P = 2 kW = 2000 W, Voltage V = 220 V, Circuit rating = 5 A.

Current drawn by the oven:

I = P / V = 2000 / 220 = 9.09 A (approximately)

The oven draws about 9.09 A, but the circuit is rated for only 5 A. Since the current drawn (9.09 A) is much greater than the circuit's safe rating (5 A), the fuse will blow (or the MCB will trip), and the circuit will be disconnected. The oven will not work.

To operate a 2 kW oven safely, the circuit must be rated for at least 10 A, and a 15 A fuse/circuit should be used. High-power appliances like ovens, geysers, and ACs should always be connected on separate high-current circuits.

Q13. What precautions should be taken to avoid overloading of domestic electric circuits?

Answer

1. Do not connect too many appliances to a single socket or circuit. Each circuit has a rated capacity (e.g., 5 A or 15 A); exceeding it causes overheating. 2. Use the correct fuse rating for each circuit — never use a fuse wire of higher rating than specified. 3. Never replace a blown fuse with a thick wire or copper wire. This defeats the safety purpose and can cause fire. 4. Distribute high-power appliances (geysers, ACs, ovens, iron boxes) across separate circuits instead of putting them all on one circuit. 5. Use MCBs instead of fuses — they trip automatically on overload and are more reliable. 6. Switch off appliances when not in use — this reduces the total load on the circuit. 7. Check wiring periodically — old, damaged, or frayed insulation can cause short circuits and overloading. 8. Do not use extension cords permanently — they are meant for temporary use and have lower current ratings. 9. Ensure proper earthing — this protects against shock in case of faults and helps fuses blow correctly.

Common Mistakes to Avoid

1. Confusing Fleming's left-hand rule with Fleming's right-hand rule. Left-hand rule is for motors (force on a current-carrying conductor). Right-hand rule is for generators (direction of induced current). Remember: Left = Motor (L for Motor/Motion), Right = Generator (R for Generator/Induced current).

2. Forgetting that field lines go N → S outside the magnet but S → N inside. Many students draw all lines from N to S. Inside the magnet, the field lines go from South to North — they form closed loops, not open curves.

3. Mixing up slip rings and split-ring commutator. Slip rings = AC generator (continuous rings, current alternates). Split-ring commutator = DC generator / DC motor (two half-rings, current direction maintained or reversed at the right time).

4. Thinking magnetic field lines can intersect. They never do. At any point, the magnetic field has exactly one direction. If lines intersected, it would mean two directions at one point — physically impossible.

5. Confusing electromagnetic induction with magnetic field creation. Electromagnetic induction is about inducing a current/EMF by changing flux — it is not the same as creating a magnetic field by passing current through a wire. A current-carrying wire produces a field (Oersted); a changing field induces a current (Faraday) — these are two distinct phenomena.

6. Forgetting that the fuse is always placed in the LIVE wire. If the fuse were in the neutral wire and it blew, the appliance would still be connected to the live wire (220 V) — extremely dangerous for anyone who touches it. The fuse must be in the live wire so that when it blows, the appliance is fully disconnected from the high voltage.

7. Wrong explanation of why a motor needs a split-ring commutator. Students often say "to supply current to the coil." The actual reason: to reverse the direction of current through the coil every half rotation so that the torque always acts in the same rotational direction, ensuring continuous rotation. Without the commutator, the coil would oscillate and stop.

8. Reversing the direction in the right-hand thumb rule. Curl fingers = field direction; thumb = current direction. Students sometimes swap these. Remember: thumb always points in the direction of conventional current.

9. Saying "field is zero inside a solenoid." It is the opposite — the field inside a long solenoid is strong and uniform. The field outside is weak (nearly zero for a long solenoid).

10. Confusing the direction of current in a generator with the direction of applied force. In a generator, you apply mechanical rotation (not electrical force). The current is the output, not the input. Do not use Fleming's left-hand rule for a generator.

Exam Checklist

[ ] I can state the properties of magnetic field lines (at least 4).
[ ] I can apply the right-hand thumb rule to find field direction around a straight wire.
[ ] I can apply Fleming's left-hand rule to determine force direction on a conductor.
[ ] I can apply Fleming's right-hand rule to determine induced current direction.
[ ] I can explain the working of a DC electric motor with the role of the split-ring commutator.
[ ] I can explain the working of an AC generator and a DC generator, and distinguish slip rings from commutator.
[ ] I can describe domestic wiring — live, neutral, earth wires and their colour codes.
[ ] I can explain the function and placement of a fuse and an MCB.
[ ] I can define electromagnetic induction and state Faraday's law.
[ ] I can calculate whether a circuit will blow its fuse given appliance power, voltage, and fuse rating.
[ ] I can list at least 5 precautions to avoid overloading in domestic circuits.
[ ] I can distinguish between electromagnet and permanent magnet with examples.

Internal Links

[Chapter 13 Guide — Magnetic Effects of Electric Current](/school/cbse/class/10/science/cbse-magnetic-effects-of-electric-current)
[All Class 10 Science Solutions](/school/cbse/class/10/science/solutions)
[Class 10 Science Subject Guide](/school/cbse/class/10/science)

Frequently Asked Questions

Stretch the thumb, index finger, and middle finger of your left hand mutually at right angles. The index finger points in the direction of the magnetic field (B), the middle finger in the direction of current (I), and the thumb gives the direction of force (motion) on the conductor. This rule is used to find the direction of force on a current-carrying conductor placed in a magnetic field and applies to electric motors.