We worked with a Daedalon apparatus in lab and set it up so the electron beam cu

Question

We worked with a Daedalon apparatus in lab and set it up so the electron beam curved into a circle. We then grabbed a magnet, aligned it with the center axis of the circle and moved it toward the tube. When the north pole of the magnet approached the beam, it deflected in a helical path away from the magnet and when we flipped it over so the south pole moved toward the beam, the beam deflected in a helical path toward the magnet.
Why does the beam go from traveling in a circular path to a helical path when the magnet gets close and why does it go away from the north pole and does the opposite for the south pole?
I would really love some help, I've been trying to figure out but haven't been able to :/

Explanation / Answer

In a magnetic field the force is always at right angles to the motion of the electron (Fleming's left hand rule) and so the resulting path of the electron is circular.

Charged particles move in circles at a constant speed if projected into a magnetic field at right angles to the field.

Charged particles move in straight lines at a constant speed if projected into a magnetic field along the direction of the field.

If the electron enters the field at an angle to the field direction the resulting path of the electron will be helical., the force on the electron is:

F =evB

A magnetic field does NOT attract or repel electrons instead it deflects the path of an electron with a force that pushes at a right angle to both the electron

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.