Explain the Hertz experiment to generate the electromagnetic wave.
Hertz experiment consists of two metallic plates of equal size, placed 60 cm apart, held parallel to each other. Two small spheres S1 and S2 are placed closed to each other and connected to the plates A and B by thick metalic rods respectively. Using an induction coil the spheres are charged to high value.
The high potential difference across the metal plates ionises the air between the spheres and allows a path for discharge of plates. During discharge, a spark is produced .The resonant frequency of the arrangement is given by
Thus highly oscillating electric field is produced across the gap between the spheres which in turn produces oscillating magnetic field of same frequency in horizontal plane perpendicular to the gap between spheres.This oscillating electric and magnetic field constitute electromagnetic waves.