e/m ratio or Charge to Mass Ratio by Thomson method

In this experiment, we determine the specific charge value e/m ratio by the Thomson method. Cathode ray tube is the main component of this experiment. As you know cathode ray tube has three components first is electron gun second is deflector plates for horizontal and vertical deflection and the third part is a fluorescent screen.

The electron gun comprises a filament. Which on heating provide thermal energy to the cathode. As a result, electrons emitted from the cathode surface. Which further moves towards the anode, the potential difference between the cathode and anode decide the kinetic energy. The deflecting plates are connected with the positive terminal horizontally and vertically.

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So providing the potential to these plates one can deflect the beam in any direction. In the (e/m ratio) Thomson method, there are two processes to determine the charge to the mass value of the electron (e/m ratio). In one case we use the two uniform circular coils while in the second one the two bar magnets.

The two bar magnets are used in this experiment. So how to originate the formula a complete theory is explained.

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