Explain Hall Effect.

Hall Effect: If a current carrying conductor is placed in a magnetic field, a voltage is produced that acts in the perpendicular direction to the current and also magnetic field. This voltage is proportional to the current and intensity of the magnetic field. This is termed as Hall Effect. When a voltage 'E_L' is applied across the opposite contacts A and B to a bar of semi- conductor material as demonstrated in the figure, a current will flow. When the bar is placed at right angles to the magnetic field 'B', an electric potential E_H is generated among the other two contacts C and D. Such voltage is a direct measure of the magnetic field strength and can be estimated by a simple voltmeter.