๐Ÿงฒ Introduction

This chapter explains how electric current produces magnetic effects and how these effects are used in devices like electromagnets, electric bells, and more. It also introduces concepts like magnetic field, right-hand thumb rule, and electromagnetic induction.

๐Ÿงญ 1. Magnetic Field and Field Lines

Magnetic Field: The region around a magnet where its magnetic force can be felt.

Field Lines: Imaginary lines representing the direction of magnetic force.

  • Outside a magnet: North to South

  • Inside a magnet: South to North

  • Closer lines = Stronger field

Properties of Field Lines:

  • Never intersect

  • Continuous closed loops

  • More concentrated near poles

๐Ÿ”Œ 2. Magnetic Field due to Current-Carrying Conductor

Oersted’s Experiment: Electric current produces a magnetic field.

๐Ÿ”ธ Magnetic Field Around:

  1. Straight Conductor: Circular field lines around the wire.

  2. Circular Loop: Magnetic field becomes stronger at the center.

  3. Solenoid: A coil of wire acting like a bar magnet when current flows.

Right-Hand Thumb Rule:

  • Thumb: Direction of current

  • Fingers: Direction of magnetic field lines

๐Ÿงฒ 3. Force on a Current-Carrying Conductor in a Magnetic Field

Magnetic Force: A conductor carrying current experiences a force in a magnetic field.

Fleming’s Left-Hand Rule:

  • Thumb: Force (Motion)

  • First Finger: Magnetic Field

  • Second Finger: Current

Used in: Electric motors

⚙️ 4. Electric Motor

A device that converts electrical energy into mechanical energy.

Working Principle: Based on magnetic force acting on a current-carrying conductor

Parts:

  • Armature (coil)

  • Commutator

  • Brushes

  • Magnet

Uses: Fans, mixers, washing machines

๐Ÿ’ก 5. Electromagnetic Induction

Electromagnetic Induction: Process of inducing current in a coil due to changing magnetic field.

Fleming’s Right-Hand Rule:

  • Thumb: Motion of conductor

  • First Finger: Magnetic field

  • Second Finger: Induced current

⚡ 6. Electric Generator

A device that converts mechanical energy into electrical energy using electromagnetic induction.

Types:

  • AC Generator

  • DC Generator

Key Parts:

  • Coil (armature)

  • Slip rings (for AC)

  • Brushes

  • Magnet

๐Ÿ” 7. Domestic Electric Circuits

Key Components:

  • Live Wire (Red): 220 V

  • Neutral Wire (Black): 0 V

  • Earth Wire (Green): Safety

Fuse: Protects appliances from overcurrent

MCB: Automatically turns off during overloading

✅ Key Points to Remember

  • Current-carrying wires produce magnetic fields.

  • Solenoids act like bar magnets.

  • Motors use Fleming’s Left-Hand Rule.

  • Generators use Fleming’s Right-Hand Rule.

  • Safe wiring includes fuse, MCB, and earthing.