Which line, A to D, correctly describes the trajectory of charged particles which enter, at right angles, (a) a uniform electric field, and (b) a uniform magnetic field?

Protons, each of mass m and charge e, follow a circular path when travelling perpendicular to a magnetic field of uniform flux density B. What is the time taken for one complete orbit?

Particles of mass m carrying a charge Q travel in a circular path of radius r in a magnetic field of flux density B with a speed v. How many of the following quantities, if changed one at a time, would change the radius of the path?

m, Q, B, v

The path of electrons in a CRO follows the path shown above. Part of the path crosses a magnetic field.

In which one or more sections of the path does a magnetic field act on the electron?

The shape of the path followed by electrons between B and C is best described by: