This is a visualization of the path of a charged particle as it enters a uniform magnetic field. Note that I have not attempted to create reasonable scales for the variables, and the absolute size of the deflection isn't indicated. But the shape of the path is true to ideal form given by the Lorentz force.

Use the right hand rule to explain the direction of the curved path when v, B, and q are all nonzero and B and q are positive.

What happens when B=0 or q=0? Why?