A charged particle enters a uniform magnetic field at an angle of 45° with the field. The path along which the particle moves in the field will be

helical with axis along magnetic field

The correct answer is Option (3) → helical with axis along magnetic field

The magnetic force on a charged particle: $\vec{F} = q \vec{v} \times \vec{B}$

Velocity component along the field ($v_\parallel$) remains unaffected; velocity component perpendicular to field ($v_\perp$) causes circular motion.

Given: particle enters at 45° → both parallel and perpendicular components exist.

Resulting motion: circular motion in plane perpendicular to B combined with uniform motion along B → helical path along the magnetic field.

Correct option: helical with axis along magnetic field