What is a Magnet & Magnetic Field?

A magnet is any object that has a magnetic field. It attracts ferrous objects like pieces of iron, steel, cobalt and nickel.

The area surrounding a magnet, in which magnetic force is exerted, is called a magnetic field.

General Properties of Magnetic lines of force

They flow from the south pole to the north pole within a material and north pole to south pole in air

They never cross one another

They all have same power

They spread out when they move from an area of higher permeability to an area of lower permeability.

Electromagnetism

Electromagnetism is the force which holds electrons and protons together inside atoms. A wire with an electric current passing through it generates a magnetic field around it this is a simple electromagnet. The strength of magnetic field generated is proportional to the amount of current. The field has a North and a South pole. It works on the same rules as a bar magnet. Like poles repel each other, unlike attract. In Simple Language Electromagnetism is said to be produced when an electrical current flows through a simple conductor such as a piece of wire or cable.

The basic law of electromagnetism is Faraday's Law of Induction.
"The induced electromotive force or emf in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit."

i.e The EMF generated is proportional to the rate at which flux is linked.

The direction of the magnetic field through a coil of wire can be found from a form of the right-hand rule.

Right Hand rule

With the thumb, index, and middle fingers at right angles to each other (with the index finger pointed straight),

the middle finger points in the direction of c when the thumb represents a and the index finger represents b.

Applications of Electromagnetism

The process of magnetic tape recording uses induced magnetism.

Mode of Transportation.

Common Speakers.

Powering Motors.

Computer monitors use solenoids to produce images.

Recording Sounds.

Magnetic fields are measured in Tesla - 1 T field exists when 1 meter of wire carrying 1 amp of current experiences 1 N of magnetism force.

There are Maxwell’s four equations that describe the electric and magnetic fields arising from varying distributions of electric charges and currents, and how those fields change in time.