Question

Discuss the Hertz experiment.

Answer 1

 

The existence of electromagnetic waves was experimentally confirmed by Hertz in 1888.

Construction:

1. It consists of two metal electrodes (S₁, S₂) which are made of small spherical metals.
2. These are connected to large spheres (A, B) and the ends of them are connected to an induction coil with a very large number of turns (H.T. Coil)

Working:

1. The induction coil produces a very high electromotive force (emf)
2. Since the coil is maintained at very high potential are between the electrodes (S₁, S₂) get ionized and spark is produced.
3. The gap between the ring type electrode kept at a distance also gets spark.
4. This implies that energy is transmitted from an electrode (S₁, S₂) to the receiver
   (x, y)
5. If the receiver (x, y) is rotated by 90° no spark is observed by the receiver.
6. This confirms that electromagnetic waves are transverse.
7. Hertz produced radio wave which also travels with the velocity of light (3 × 10⁸ ms^-1).