Cathode Rays
Physics: AQA A Level, topic 12.1.1
Production of Cathode Rays
Cathode rays are used in older screens.
Cathode rays
- A cathode ray is another name for a beam of electrons.
- The name cathode ray comes from the fact that the beams appear to originate at the cathode.
- Cathode rays are most commonly produced in discharge tubes.
Discharge tubes
- A discharge tube is an evacuated glass tube which has a potential difference applied across it.
- The potential difference causes electrons to jump from the cathode of the tube to the anode:
- The cathode is the negative end.
- The anode is the positive end.
- When these electrons hit the other end of the glass tube, they release energy as visible light.
Impact of cathode rays
- Cathode rays taught us a lot about electrons, such as:
- They have properties such as mass, momentum, and energy.
- Their charge.
- Their properties.
Test yourself on Cathode Rays
Which of these statements are true about cathode rays?
The anode has what charge?