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When a current carrying conductor is placed in a magnetic field, a potential difference is generated in the direction perpendicular to both the current and magnetic field. This phenomenon is called Hall Effect. It arises from the deflection of charge carriers to one side of the conductor as a result of the magnetic force they experience. The Hall effect gives information regarding the sign of the charge carriers and their density; it can also be used to measure the magnitude of magnetic fields.
The figure shows the Hall Effect. The figure implies that if an electric current flows through the conductor in the given magnetic field B, the magnetic field exerts a transverse force on the moving charge carriers which tends to push them to one side of the conductor. A buildup of charge at the sides of the conductors will balance this magnetic influence, producing a measurable voltage between the two sides of the conductor.
The transverse voltage measured in the Hall Effect has its origin in the magnetic force on a moving charge carrier. The Hall voltage is given by,
where I= current flowing through the conductor, B = magnetic field, n= density of charge carriers, e = electronic charge, and d = thickness of the conducting slab.
The Hall Effect is a conduction phenomenon which is different for different charge carriers. In most common electrical applications, the conventional current is used as it makes no difference whether we consider positive or negative charge to be moving. But the Hall voltage has a different polarity for positive and negative charge carriers.
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