Discuss the history of em waves brief.

Explanation

History of electromagnetic waves : In 1865, Maxwell suggested that a changing electric field gives rise to a changing magnetic field and vice - versa. It means that when either of the fields changes with time, the other field is induced in space. The superposition of these time varying electric and magnetic field give rise to electromagnetic disturbance. Such disturbance can propagate through the space even in the absence of material medium. In other words, electromagnetic disturbance (or wave ) can propagate through vacuum.
In 1887, a German Scientist Hertz, first of all gave a practical demonstration of the production of electromagnetic waves using an oscillatory circuit. However, the electromagnetic waves produced by Hertz were to large wavelength and hence small frequency which could not be detected over a large distance. Just seven years after Hertz.s observation, an Indian Scientist ranging from 5 mm to 25 mm. But his experiment remained confined to the laboratory. In 1895, Marconi made an important discovery which made electromagnetic waves of commericial value. He was successful in transmitting electromagnetic waves upto a few kilometers.