Name: Electrovalency
Uploaded: 2019-07-19
Duration: 1 min 51 s
Description: Do you know how chemical bonds are formed? They are formed in order to attain a stable electronic configuration. Let's watch the video to learn about the pro...

Question

Explain, how cathode rays are formed from the gas taken in the discharge tube?

Accepted Answer

A long glass discharge tube $G$ is sealed at the two ends with electrode $A$ and $B$ . A side tube $S$ is also fused to the tube $G$ , which is connected to a vacuum pump to reduce the pressure inside the tube. Electrodes are connected to the electric power. The electrode $A$ is connected to the cathode (negative terminal) and the electrode $B$ is connected to the anode (positive terminal).

At low pressure cathode rays are produces. If the pressure of the air or gas inside the tube falls to about $0.001 mm$ , then the discharge inside the tube completely disappears, that is, there is no light emitted by the air. The tube appears completely dark. However, the glass wall of the tube exactly opposite to the cathode glows with a greenish-yellow light, known as fluorescence. This observation clearly demonstrates that some invisible rays are coming from the cathode which travel along the straight line and strike the glass wall opposite to the cathode. Since these rays were coming from the cathode, these are known as cathode rays.

Explain, how cathode rays are formed from the gas taken in the discharge tube?

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