What are cathode rays?
Streams of electrons produced in a discharge tube.
AQA A-level Physics (7408) · 3.12.1.1
Revise AQA A-level Physics (7408) specification point 3.12.1.1, Cathode rays (A-level only), with free active-recall flashcards. Flip through the set or review every question and answer below.
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What are cathode rays?
Streams of electrons produced in a discharge tube.
What conditions are used to produce cathode rays in a discharge tube?
Gas at very low pressure and a high potential difference between a negative cathode and a positive anode.
How does the electric field affect electrons released from the cathode?
It accelerates them towards the anode.
Why is the gas pressure kept very low in a cathode-ray discharge tube?
To reduce collisions, allowing electrons to travel through the tube.
How can ionisation of the remaining gas sustain a cathode-ray discharge?
Positive ions move towards the cathode and strike it, releasing further electrons.
How can electrons form a cathode-ray beam beyond the anode?
They pass through an opening in the anode and continue beyond it.