The question asks what happens to the speed of a charged particle moving through a region where only magnetic forces are acting on it. To answer this, let's examine the nature of magnetic forces.

Magnetic forces do not do work on charged particles. This is because the magnetic force is always perpendicular to the velocity of the particle (as defined by the right-hand rule in physics). As a result, the magnetic force changes the direction of the particle's velocity, not its speed. Since work is related to changes in kinetic energy (which depends on speed), the speed of the particle remains constant.

So, the correct answer to this question is:

• The particle's speed stays constant.

Would you like further clarification on this, or perhaps details on how magnetic forces interact with charged particles?

Here are 5 questions to expand on this topic:

1. How does the right-hand rule apply to determine the direction of magnetic force on a particle?
2. What is the relationship between the Lorentz force and a charged particle in a magnetic field?
3. How does the velocity vector of the particle evolve if the magnetic field is uniform?
4. What is the impact of an electric field acting alongside a magnetic field on a charged particle’s motion?
5. Can a magnetic field change the kinetic energy of a charged particle?

Tip: Remember, magnetic forces influence the direction of a particle's velocity but not its magnitude (speed).