Radiation is the emission and propagation of energy through matter.
We have electromagnetic radiation which are of two categories which are:
  ionization and non ionization radiation. Ionizing radiation are the electromagnetic radiation that carries sufficient energy to bring about changes in atoms that it strikes. There are three types of ionizing radiation which are
Alpha particles
Beta particles
Gamma rays
Have a short break

Alpha particles
They are positive, they possess high ionizing power. They have low penetrating power,they are deflected towards negative charge.
They are stopped by sheet of paper.

Beta particle:
They are negatively charged, they possess moderate ionizing power.They have medium penetrating power,they are deflected towards the positive charge.
They are stopped by aluminium foil

Gamma ray
Beta particle:
They are neutral, they possess low ionizing power.They have high penetrating power,they arenot deflected.
They are stopped by concrete.
Radiation causes sicknesses which are
2.Cancer e.t.c
This is due to the over exposure to unsealed and sealed radiation source.
Some terms i n radiation study are
Maximum permissible dose
Absorbed dose