Correct Answer - Option 2 : is used in various sensor applications
Hall effect:
Hall Effect is basically the production of voltage (known as hall voltage) across a conductor transverse to an electric current and to an applied magnetic field perpendicular to the current.
The Hall voltage VH developed across the Hall sensor is given by
\({V_M} = \frac{{KBI}}{t}\)
Where B is the magnetic flux density.
I is the current through the Hall effect sensor.
From the above relation, the Hall voltage is directly proportional to both l and B.
Application:
Hall effect has a lot of sensor applications.
Hall effect sensing devices are becoming popular in a wide range of industrial and consumer products, such as sewing machines, automobiles, machining tools, medical equipment, and computers.
