Question

When a charged particle moves along a helical path in a uniform magnetic field, which component determines the pitch of the path? the velocity component perpendicular to the magnetic field vector the velocity component parallel to the magnetic field vector the acceleration component perpendicular to the magnetic field vector the acceleration component parallel to the magnetic field vector the acceleration component radially inward the acceleration component radially outward

Answer 1

the velocity component parallel to the magnetic field vector

Step-by-step explanation:

When a charged particle moves in a helical path, we can decompose its velocity into two parts v_parallel and v_perpendicular to the magnetic field.

Let's analyze which component receives a force

F = q vxB

the bold letters indicate vectors, in the vector product if the two vectors are parallel the angle is zero and the sin 0 = 0 for which there is no force. therefore the velocity parallel to the field remains constant

If the two vectors are perpendicular, the angle is 90º and the sin 90 = 1, for which there is a force, which has a radial direction and consequently a centripetal acceleration that gives a circular path that does not remove the particle from the magnetic field

When checking the different answers, the correct one is: the velocity component parallel to the magnetic field vector