GP Magnetism

A force F, acting on an electric charge q, in presence of an electromagnetic field, moves the charge parallel to the magnetic field with velocity v. Then F is equal to (where E and B are electric field and magnetic field respectively)

  1. q(v x B)
  2. q(v x E)
  3. qB
  4. qE

Answer

Lorentz force is the vector sum of force due to electric field and the force due to magnetic field.

F = qE + q(v x B)

Since, charge is moving parallel to magnetic field, force due to magnetic field is zero.

The correct option is D.