Electron motion – circular or helical

QUESTION:

(a) How can a charge move through a magnetic field without ever experiencing any magnetic force?
(b) How are magnetic field lines similar to electric field lines? How are they different?
(c) What makes the path of the charge particle circular or helical in a uniform magnetic field?

Answer:

(a) the charge can move through the field if it is moving along the lines of the magnetic field. Only if it moves at an angle to the magnetic field will it experience a force – the maximum force will be felt when it is moving at right angles to the field.

(b) They show the strength of the field but a magnetic field and not an electric field

(c) The path will be circular if the charge moves at right angles to the field. It will be helical if it moves at an angle to the direction of the field.

See also: Helical motion