Objective: Determine the specific charge of an electron
In the fine-beam tube, the path of electrons in a uniform magnetic field can be observed as a clearly delineated ray. This means that the radius of the circular path can be directly measured with a simple ruler. From the path radius r, the magnetic field B and the electron gun’s accelerating voltage U the specific charge of an electron e/m can be calculated.
![Experiment: Fine-Beam Tube (115 V, 50/60 Hz), 8000667 [UE3070700-115], Electron tubes](/imagelibrary/UE3070700-115/UE3070700-115_01_Experiment-Fine-Beam-Tube-115-V-5060-Hz.jpg)
![Experiment: Fine-Beam Tube (115 V, 50/60 Hz), 8000667 [UE3070700-115], Electron tubes](/thumblibrary/UE3070700-115/UE3070700-115_01_1200_1200_Experiment-Fine-Beam-Tube-115-V-5060-Hz.jpg)
