MAGNETISM

Link Magnet
three ways of magnetizing : - Sweeping
- Using a direct current
- Magnetic induction

Magnet material : 1. Non magnetic - Paramagnetic matrials, example : platinum and aluminum
- Diamagnetic materials, examples : bismuth, zinc and sodium
chloride
2. Ferromagnetik materials, examples : irons, steel, nickel, and cobalt

Magnet comprises : - North pole ------------ interaction --------------- Attractive
- South pole ------------ between poles -------------- Repulsive

Three ways of demagnetizing :

1. Heating
2. Flowing an alternating current
3. Hammering

Affecting factors making a magnet by using electric current :
- Number of loops
- Electric current
- Type of core material

Electromagnet used in :- Doobells
- Electromagnetic relays
- Telephones

CAHAYA

Pengertian Cahaya

Cahaya merupakan gelombang elektromagnetik.
Hukum Pemantulan Cahaya:

1. Sudut datang sama dengan sudut pantul
2. Sinar datang, garis normal dan sinar pantul terletak pada bidang datar