Which one of the following statements is not correct?

The cathode rays originate from cathode and proceed towards the anode in a cathode-ray discharge tube.

The television picture tubes are nothing but cathode-ray tubes.

The cathode rays themselves are not visible.

The characteristics of cathode rays depend upon the nature of the gas present in the cathode-ray tube.

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CDS-1 – 2017

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Statement D is incorrect. Cathode rays are streams of electrons emitted from the cathode in a discharge tube. The properties of electrons, such as charge and mass, are fundamental constants and do not depend on the material of the cathode or the type of residual gas present in the tube. J.J. Thomson’s experiments showed that the charge-to-mass ratio of cathode rays was always the same, regardless of the source material.

Statements A, B, and C are correct. Cathode rays originate from the negatively charged cathode and travel towards the positively charged anode (A). Older television and computer monitors used Cathode Ray Tubes (CRTs) to produce images (B). The beam of electrons itself is not visible to the naked eye; the light is produced when the electrons strike a fluorescent screen (C).

The discovery and study of cathode rays were crucial in the development of the understanding of the electron as a fundamental particle of matter.

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