Question

Given a permanent magnet with known magnetic poles and a beam of electrons, how can you show that the electrons are negatively charged

Answer 1

Answer:

To prove that the electron is negatively charged, first we orient the direction of the magnetic field of the permanent magnet to enter into this computer screen.

Next we focus the beam of electrons to cut across the magnetic field perpendicularly, flowing from the right side of this screen to the left side.

If the electron beam is deflected upwards, then the electrons in the electron beam are negatively charged.

To check, we know that Lorentz left hand rule for a negatively charged particle moving through a magnetic field states that "if the left hand is held out with the fingers parallel to one another, and the thumb at a 90° angle to the rest of the fingers, then the fingers represents and points in the direction of the magnetic field, and the thumb represents and points in the direction of the negative charge through the magnetic field. The palm of the left hand will push in the direction of the force on the negatively charged particle."