A thick metal slab carries a current I. A uniform magnetic field B points perpendicular to the slab (and into the page). If point P on the slab is at a higher potential than point , what can we say about the charge carriers that produce the current in the slab?

http://courses.washington.edu/phys431/hall_effect/hall_effect.pdf

Think about conventional current.

To determine what we can say about the charge carriers that produce the current in the slab, let's analyze the given information.

First, we know that the magnetic field is pointing perpendicular to the slab, which means it is parallel to the current flow. This indicates that the movement of charge carriers within the slab is being influenced by the magnetic field.

Second, we are told that point P on the slab is at a higher potential than point O. This implies that there must be an electric field present within the slab, causing the potential difference.

Based on this information, we can infer that the current in the slab is likely due to the motion of charged particles in response to both the electric field and the magnetic field.

To determine the nature of the charge carriers, we can apply the right-hand rule. If we align our right-hand thumb with the direction of the current flow (from O to P), and if our fingers curl in the direction of the magnetic field (into the page), then our palm will point in the direction of the force acting on the charge carriers.

Since the slab is experiencing a higher potential at point P, the force on the charge carriers must also be directed from O to P. This means that the charge carriers within the slab must have a negative charge, as the force is opposite in direction to the conventional current flow.

Therefore, we can conclude that the charge carriers in the slab are likely negative electrons. They are moving in response to both the electric field, which creates the potential difference between points O and P, and the parallel magnetic field, which influences their motion within the slab.