Question

In which of the cases below an electric charge experiences a force due to a magnetic field?

• A. When it is stationary
• B. When it moves parallel to the magnetic field
• C. both (a) and (b) above
• D. When it moves perpendicular to the field

Answer 1

The correct option is D When it moves perpendicular to the field

Force on a charge placed in magnetic field is given by, $F=q\left(VXB\right)$
so the charge will feel no force if it is stationary or when it is moving parallel to the field lines.

When charge is moving in the direction perpendicular to the magnetic field then it will experience the magnetic force.