Today in AP Physics 2, students determined the mass of the electron. The students deflected an electron beam in a vacuum tube with the magnetic field of the solenoid. By measuring the current in the solenoid, the accelerating potential in the vacuum tube, and the radius of curvature of the electron beam, students were able to calculate the mass of the electron. There is a lot of uncertainty in the radius measurement, but the calculated mass is still fairly close to the expected value!
4 thoughts on “Day 89: Mass of the Electron Lab”
I came across this in a search for ideas for labs for my AP Physics 2 class. How exactly is this lab done? I have solenoids like this in my room, but what did you use for the electron gun? This looks like an interesting lab. Thanks!
We use a 6AF6G vacuum tube to generate the electron beam. The vacuum tube is mounted on a wooden base over which the solenoid fits nicely.
Here is the entire lab.
Thank you! I appreciate it!