Step-by-step explanation:
Thompson's experiment, also known as the Cathode Ray Tube experiment, was conducted to investigate the properties of cathode rays, which are streams of electrons emitted from a negatively charged electrode called a cathode. The experiment involved using an electric field and a magnetic field to deflect the cathode rays and study their behavior. When the electric field was switched on, it caused the cathode rays to be deflected towards the positive electrode (anode) of the tube. This is because the electric field exerted a force on the negatively charged cathode rays, causing them to move towards the positively charged anode. However, when the magnetic field was applied perpendicular to the electric field, it caused the cathode rays to deflect again, this time in a direction perpendicular to both the electric and magnetic fields. The direction of deflection was dependent on the polarity of the magnetic field. By adjusting the strength and direction of the magnetic field, Thompson was able to push the cathode rays back to their original position, essentially canceling out the deflection caused by the electric field. This is because the magnetic force acting on the cathode rays was perpendicular to the electric force, and by adjusting the strength and direction of the magnetic field, Thompson was able to balance the forces and bring the cathode rays back to their original path. Thompson's observation that the magnetic field could be used to push the cathode rays back to their original position demonstrated the interaction between electric and magnetic fields, and provided evidence for the particle-like behavior of electrons.