Electromagnetic Radiation

Aim

To demonstrate the transmission of electromagnetic radiation and the relationship between the electrical and magnetic fields.

Apparatus

  • Metre wavelength apparatus
  • Electric and magnetic dipole antennas
  • Demonstration galvanometer

Electromagnetic Radiation 1 Electromagnetic Radiation 2

Description

The apparatus produces e.m. radiation of wavelength 1-2 metres. The transmitter is positioned at one end of the lecture room with the dipole antenna (electric) connected to the wooden gallows.

The receiver may consist of either an electric or magnetic dipole connected to the demonstration galvanometer. The sensitivity of the galvanometer must be set to maximum if the magnetic dipole is acting as the receiver.

If either antenna is turned so that it points END ON to the other aerial reception falls showing that the electric field is perpendicular to the line of propogation and parallel to the transmitting aerial.

Using the electric dipole aerial at the transmitting end and the magnetic dipole as receiver the perpendicular relationship of the electric and magnetic field vectors may be demonstrated.