All electromagnetic waves travel at the speed of light, and can travel through a vacuum
Radio emitted when
Electrons oscillate in a conductor (transmitter)
Radios absorbed when
Electrons oscillate in a conductor (aerial)
Microwaves emitted when
Electrons oscillate in a conductor (transmitter)
Microwaves absorbed when
Electrons oscillate in a conductor (aerial) and molecules rotate
Infrared emitted when
Atoms vibrate and lose kinetic energy
Infrared absorbed when
Atoms vibrate and gain kinetic energy
Visible light emitted when
Electrons fall from high energy level to low energy level
Visible light absorbed when
Electrons jumper from low energy level to high energy level
Ultraviolet emitted when
Electrons fall from higher energy level to lower energy level
Ultraviolet absorbed when
Electrons juml from lower energy level to much higher energy level. High energy UV may cause ionisation
X-rays emitted when
Fast moving electrons collide with a metal target. Electrons lose kinetic energy
X-rays absorbed when
Electrons in atoms gain energy and leave the atom completely (ionisation)
Gamma rays emitted when
Radioactive decay of radioactive nuclei. Nuclear processes in star
Gamma rays absorbed when
Electrons in atoms gain energy and leave the atom completely (ionisation)