Suppose I launch a charged particle into a uniform magnetic field. The particle will trace out a circular path in the field. Which of the following changes will decrease the radius of the circular path? Decrease the strength of the magnetic field Increase the mass of the particle Increase the charge on the particle Increase the volume of the particle Increase the speed of the particle

increase the charge

Explanation:

The force acting on charge particle when moving perpendicular to the magnetic field

F = q v B

The centripetal force is given by

F = mv^2 / r

Comparing both, we get

r = m v / B q

That means the radius of the circular path depends on mass of the charge particle, velocity of the charge particle, magnetic field strength and charge of the particle.

To decrease the radius:

1. increase the charge

2. increase the magnetic field strength

3. decrease the speed

4. decrease the mass