Deflect a beam of electrons. Classes Used: Phys 102, 108

Updated on: 06/13/13

To show the force on a beam of electrons when a magnetic field is applied. To show that a flow of electrons is equivalent to a conventional current in the opposite direction.

Oscilloscope with case opened, bar magnet

The special oscilloscope can be set up to show the exposed neck of the tube. When a magnet is brought near the neck of the oscilloscope, the electron beam will move.

You can use the right-hand rule to label an unknown magnet by observing the deflection of the electron beam. Alternately, if the polarity is known, you can predict the deflection.