Question

A proton moving with velocity \( V \) in a non-uniform magnetic field traces a path as shown in the figure. The path followed by the proton is always in the plane of the paper. What is the direction of the magnetic field in the region near points P, Q, and R? What can you say about relative magnitude of magnetic fields at these points?

Hint:

Use the right-hand rule to determine the direction of the magnetic field based on the direction of motion of a positively charged particle.

Answer 1

The direction of the magnetic field at points P, Q, and R can be determined using the right-hand rule for the motion of charged particles in a magnetic field. The proton experiences a force that is always perpendicular to both its velocity and the magnetic field.
At point P, the magnetic field is directed into the page.
At point Q, the magnetic field is directed out of the page.
At point R, the magnetic field is again directed into the page.
The relative magnitude of the magnetic fields increases as the proton moves from point P to point Q, and decreases again as it moves from Q to R.