A region has a uniform magnetic field in it. A proton enters the region with a velocity, making an angle of 45° with the direction of the magnetic field. In this region the proton will move on a path having the shape of a:

helix

The correct answer is Option (4) → helix

Since the proton enters the magnetic field at an angle (45°), it motion will be a helix (spiral) with a circular trajectory in the plane perpendicular to the magnetic force.