Mayalab Instrument

A Cathode Ray Discharge Tube (commonly called a Cathode Ray Tube or CRT) is a device used to study the behavior of electrons (cathode rays) in a vacuum. It played a crucial role in the discovery of the electron  Structure of a Cathode Ray Discharge Tube:

1. Glass Tube

   • A long, sealed, evacuated glass tube (low-pressure gas inside).

2. Electrodes

   • Cathode (−): Negatively charged metal plate.

   • Anode (+): Positively charged metal plate.

   • These are connected to a high-voltage power supply.

3. Fluorescent Screen / Coating

   • Inside surface is coated with fluorescent material like zinc sulfide, which glows when struck by cathode rays.

4. Vacuum Pump

   • Maintains low pressure (nearly a vacuum) inside the tube.

• When high voltage is applied between the electrodes:

  • The cathode emits electrons (called cathode rays).

  • These rays travel in straight lines from the cathode to the anode.

  • When they hit the fluorescent screen, they cause it to glow, producing visible ligt 

  • Key Observations from Cathode Ray Experiments:

• Cathode rays travel in straight lines.

• They are negatively charged (bent by electric/magnetic fields).

• They have mass (cause a paddle wheel to rotate).

• They can produce heat and X-rays when they hit metal targets.