Question

Name the three main parts of the cathode ray tube.

Answer 1

Hint: In this question we have been asked to name the three main parts of the cathode ray tube. Therefore, to answer this question, we shall first discuss the construction of cathode ray tubes. We shall then discuss the main parts of the cathode ray tube along with their working and the need in the tube. The television set in every household has a cathode ray tube that displays the images.

Complete step by step answer:
A cathode ray tube is a vacuum tube in which images are produced when an electron beam strikes a phosphorescent surface. A Cathode ray tube is made of the electron gun assembly, the phosphor viewing surface, and the glass envelope. A heated cathode surrounded by a metal anode makes the electron gun assembly.
  

The first important part of the cathode ray tube is the heated metal cathode also known as the electron gun. The heat is supplied to the cathode which gets the electrons heated up. These electrons then start ejecting as a stream of negatively charged electrons which later accelerates towards the phosphor screen.
The second important part of the CRT is the phosphor screen. The function of this fluorescent screen is to convert electrical signals into visual patterns.
The third import part of the CRT is the deflecting system. The function of the deflector system is to deflect the electron beam horizontally or vertically. Therefore, it is also known as electron beam deflector.

Note:
J.J Thompson carried out an experiment with the cathode rays showing that all atoms contain tiny negatively charged particles. When the electron beam hits the phosphor screen, the phosphor sparks or emits light. In Thompson’s experiment, the cathode ray deflected away from the negatively charged electric plates and attracted towards the positively charged electric plates. This helped him prove that cathode rays were composed of tiny negatively charged particles.