Percobaan Sinar Katoda JJ Thomson

Introduction

This tutorial guides you through the cathode ray experiment conducted by J.J. Thomson, a fundamental experiment that led to the discovery of the electron. Understanding this experiment is crucial for grasping the basics of atomic structure and the behavior of charged particles.

Step 1: Setup the Cathode Ray Tube

• Gather Materials

  • Cathode ray tube (CRT)
  • Power supply
  • Electrical connections
  • Emission source (usually a heated filament)

• Assemble the Equipment

  • Connect the cathode ray tube to the power supply.
  • Ensure the filament is connected properly to emit electrons.

• Create a Vacuum

  • Ensure the cathode ray tube is under a vacuum to prevent air resistance, which can interfere with the electron flow.

Step 2: Power the Filament

• Turn on the Power Supply

  • Activate the power supply to heat the filament.

• Observe Electron Emission

  • Notice the emission of electrons from the cathode when the filament is heated. The electrons will travel towards the anode inside the tube.

Step 3: Apply Electric Fields

• Set Up Electrodes

  • Place two charged plates (anode and cathode) inside the cathode ray tube.

• Adjust Voltage Levels

  • Use the power supply to create an electric field between the plates. Alter the voltage to observe how the electrons are deflected.

• Observe Deflection

  • Note the direction of electron deflection. Electrons will move towards the positively charged anode due to their negative charge.

Step 4: Analyze Results

• Measure Deflection Angles

  • Use a protractor or similar tool to measure the angles at which the electrons deflect.

• Understand the Implications

  • The amount of deflection is proportional to the strength of the electric field and the charge-to-mass ratio of the electrons.

• Connect Findings to Atomic Theory

  • Discuss how these findings support the existence of negatively charged particles (electrons) and contribute to the development of atomic models.

Conclusion

By following these steps, you have recreated J.J. Thomson's cathode ray experiment, gaining insight into the existence of electrons. This experiment not only laid the groundwork for modern atomic theory but also opened the door to further discoveries in physics. For further exploration, consider looking into the Rutherford gold foil experiment, which builds on Thomson's findings to describe the nucleus of the atom.