One-Shot Session on Magnetic Effects of Electric Current

Introduction

• One-shot session intended as a quick, intensive review
• Focus on both revision and new learning
• Important for classes 11th and 12th

Hans Christian Ørsted's Discovery

• Discovered relationship between electricity and magnetism
• Current passing through a wire causes a compass needle to deflect
• Key Concept: Current-carrying wire acts as a magnet

Properties of Magnetic Field Lines

• Direction: North to south outside the magnet; south to north inside
• Magnetic field lines form closed loops
• Strength: Closeness of lines indicates magnetic field strength
• Field lines do not intersect

Current-Carrying Conductor

• Straight Wire: Magnetic field in concentric circles
• Right-Hand Thumb Rule: Thumb in the direction of current, fingers curl in direction of magnetic field lines
• Effect of Current: Reversing current reverses magnetic field direction

Magnetic Field due to a Circular Coil

• Magnetic Field Direction: Curl fingers in current's direction, thumb points in magnetic field direction
• Strength increases with number of turns and current

Solenoid and Bar Magnets

• Solenoid acts like a bar magnet
• Strong uniform field inside, similar to bar magnet's field

Factors Affecting Magnetic Field Strength in Conductors

• Amount of Current: More current, stronger field
• Number of Turns: More turns, stronger field
• Insertion of Iron Rod: Increases strength by focusing field lines

Force on a Current-Carrying Conductor (Fleming's Left-Hand Rule)

• Force experienced in magnetic field
• Maximum Force: When field and current are perpendicular
• FBI Rule: Force (F), Magnetic Field (B), Current (I)

Application: Electric Motor

• Converts electrical energy to mechanical energy
• Uses split-ring commutator to reverse current direction

Electromagnetic Induction (EMI)

• Induced current when there's a change in magnetic field
• Faraday's Law: Relative motion between magnet and conductor induces current
• MIB Rule: Motion (M), Magnetic Field (B), Induced Current (I) via right hand

Practical Applications

• Electric Motor: Uses commutator to maintain current direction for constant rotation

Key Experiments

• Kicking Wire Experiment: Demonstrates force on a conductor
• Magnetic Induction Experiment: Demonstrates induced current with changing magnetic field

Homework Question

• Analyze a given scenario and use concepts learned to determine the outcome

Conclusion

• Revise thoroughly and prepare for question-solving in the next session on Monday