The magnetic force on a moving charge does no work on it because the force is
- A. very small
- B. always perpendicular to the velocity
- C. always opposite to the velocity
- D. not a real force
Explanation
Work is the dot product of force and displacement, and a force at right angles to the motion contributes nothing, so the kinetic energy and speed of the particle never change. Only the direction of travel is altered. This is why a magnetic field can steer a particle beam but cannot accelerate it, which is the job of the electric field in an accelerator.
Related questions
A charged particle moving parallel to a magnetic field experiences a force of
A charged particle entering a uniform magnetic field at right angles to it follows
The radius of the circular path of a charged particle in a magnetic field is given by
In a mass spectrometer, ions of the same charge and speed but different masses are separated because