Electromagnetic forces

Magnetism and Electromagnetism

Racheal Maria M

Contents

• Introduction

• Magnetic Field

• Magnetic Field Lines

• Magnetic Effect of Current

• Electric Motor

Introduction

* Magnets are attractive. Why?

* Natural vs Artifical Magnets

* Strongest natural magnet- Lodestone

Magnetic Field

• An invisible field(space) around all magnets attracts mag.materials

• 2 forces experienced- Attraction and repulsion

• Direction is found using a compass

• Can penetrate through all kinds of materials

• Denoted by B

• unit: Tesla

Magnetic Field Lines

• The direction of the magnetic field is tangent to the field line at any point in space. A small compass will point in the direction of the field line.

• The strength of the field is proportional to the closeness of the lines. It is exactly proportional to the number of lines per unit area perpendicular to the lines (called the areal density).

• Magnetic field lines can never cross, meaning that the field is unique at any point in space.

• Magnetic field lines are continuous, forming closed loops without beginning or end. They go from the north pole to the south pole.

• A current carrying straight conductor has magnetic field in the form of concentric circles; around it.

• Magnetic field of current carrying straight conductor can be shown by magnetic field lines.

• The direction of magnetic field through a current carrying conductor depends upon the direction of flow of electric current.

• The direction of magnetic field gets reversed in case of a change in the direction of electric current.

Electric Motor

• An electric motor is an electrical machine that converts electrical energy into mechanical energy.

• Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft.

Multiple Choice

Unit of Magnetic Field

• Tesla

• Weber

Fill in the Blank

Magnetic field lines are ______ curves

Open Ended

Write the properties of Magnetic Field

Fill in the Blank

Electromagnetic Induction was discovered by

Thank You