List and explain the functions of the Four basic parts of a cathode ray tube ?

1. Electron gun: The electron gun is responsible for generating a focused beam of electrons. It consists of a heated cathode that emits electrons, an anode that accelerates the electrons, and focusing electrodes that help to concentrate the electron beam into a narrow stream.

2. Deflection system: The deflection system is used to control the movement of the electron beam across the screen of the cathode ray tube. It typically consists of two sets of electromagnetic coils, one for horizontal deflection and one for vertical deflection. By varying the current passing through these coils, the position of the electron beam can be controlled to create images on the screen.

3. Phosphor-coated screen: The phosphor-coated screen is the surface on which the electron beam strikes to produce light. The screen is coated with phosphor, a material that emits light when excited by electrons. Different phosphors can produce different colors of light, allowing for the creation of color images on the screen.

4. Glass envelope: The glass envelope is the outer casing of the cathode ray tube that encloses all the internal components. It is typically made of thick, leaded glass to contain the high voltages used in the tube and to protect the delicate internal components from external damage. The glass envelope also helps to maintain a vacuum inside the tube, which is necessary for the proper operation of the electron gun and the electron beam.