Electromagnetism

Magnetic Force
Magnetic Field – A distribution of a magnetic force in the region of a magnet.
Law of magnetic forces: Opposite Attracts / Same Repels

North attracts to South and repels North, vice versa

A good way to show magnetic field is to spread iron fillings near a magnet. 

Earth itself is an enormous magnetic field, produced by the flow of lava in the core.
Compasses always point to the north because it is attracted by the Earth’s magnetic field. However, we know that opposites attract, thus the Geographical North Pole is known as the physical/magnetic south, and vice versa.
 

Domain Theory of magnets: All large magnets are made up of many smaller magnets, called dipoles. Their magnetic force is only “activated” or in full power when all domains are lined up. 

Electromagnets:
In earlier days, magnetism and electrostatics were not considered the same field of study.  Thus, people did not know how to apply magnetism in the field of electrostatics, which is essential for many technologies today.
However, scientists have broken the barrier between magnetism and electrostatics, namely Gilbert and Oersted.
 

Oersted’s Principle: Charge moving through a conductor produces a circular magnetic field around the conductor.
 

(Both follow conventional current flow)
Right Hand Rule #1: 

 
Right Hand Rule #2:

 

Electromagnet Factors
·    Current B2 = B1(I2/I1)
·    Number of turns in the coil B2 = B1(n2/n1)
·    Type of Material
·    Size