Electromagnetic waves are transverse waves that transfer energy from the source of the waves to an absorber
Electromagnetic waves form a continuous spectrum and they travel at the same velocity through a vacuum or air
Electromagnetic spectrum
A) Long wavelength
B) Low frequency
C) High frequency
D) Short wavelength
Types of wave
A) Radio waves
B) Microwaves
C) Infrared
D) Visible light
E) Ultraviolet
F) X-rays
G) Gamma rays
Our eyes only detect visible light and so detect a limited range of electromagnetic waves
Different substances may absorb, transmit, refract or reflect electromagnetic waves in ways that vary with wavelength
Radio waves can be produced by oscillations in electrical circuits
When radio waves are absorbed they may create an alternating current with the same frequency as the radio wave itself, so radio waves can themselves induce oscillations in an electrical circuit
Gamma rays originate from changes in the nucleus of an atom
Changes in atoms and the nuclei of atoms can result in electromagnetic waves being generated or absorbed over a wide frequency range
Ultraviolet waves, X-rays and gamma rays can have hazardous effects on human body tissue
