Question

Why does a magnetic force change only the direction of a charged particle's motion and not its speed?

पर्याय

• The magnetic force is always parallel to the velocity of the particle, so it only accelerates the particle forward

• The magnetic force is always anti-parallel to the velocity, reducing the particle's speed to zero

• The magnetic force is always perpendicular to the velocity of the particle, so it has no component along the direction of motion

• The magnetic force acts at an angle of 45° to the velocity, so its effects on speed and direction cancel out

Answer 1

The magnetic force is always perpendicular to the velocity of the particle. Because force has no component along the direction of motion, no work is done by the magnetic force, kinetic energy remains constant, and speed does not change — only direction changes.