Oscillating electric and magnetic fields perpendicular to each other cause disturbances in space. These disturbances propagate in a direction perpendicular to both the electric and the magnetic fields and are called electromagnetic waves.
The electromagnetic spectrum is classified as
- Gamma rays
- Ultra-violet rays
- Visible light
- Infra-red rays
- Microwaves and
- Radio waves
1888 – Hertz produced electro magnetic waves of wavelength about 6m.
1895 – J.C. Bose, an Indian scientist produced electromagnetic waves of wave length ranging from 5 mm to 25 mm.
1899 – G. Marconi was the first to transmit electromagnetic waves and establish wireless communication across the English Channel.