Question

Will hall coefficient change sign if the direction of applied mag field reverses?

Answer 1

When a magnetic field is applied at right angle to a conductor carrying current, a voltage is developed across the conductor in a direction perpendicular to both , the current and the magnetic field. This is called Hall voltage.

The Hall coefficient/constant is a constant for the given conductor. On reversing the direction of (a) magnetic foield (b) current, or both the polarity of the Hall voltage developed changes with each reversal, but the Hall coefficient does not change sign.

Importance of Hall Effect:

It gives the following important quantities:

The sign of the current carriers is determined

The magnitude of the Hall coefficient, the number of charge carriers per unit volume can be calculated.

The mobility of charge carriers can be determined directly.

Hall effect can be used to decide if the material is a metal, semiconductor or an insulator.