Question

In a cathode ray tube, the screen is coated with fluorescent material.
A) It produces spots on the screen
B) Beam of light is not in a straight line
C) Light deviates away after striking
D) None of these

Answer 1

Hint: The answer here is dependent on the general principle of cathode ray tube that includes the instrumentation part and thus this fact helps you to approach the correct answer.

Complete Solution :
In our lower classes, we have come across the chapters that deal with the analysis and also to produce images in the electrical devices like X - ray diffraction and several other diffraction patterns that have wide applications in daily life.
- Now, one among those are the cathode ray tubes that basically are called CRT's. These are the devices used for the production of images on the screen that work on the principle of producing or scattering electrons through the electrons gun and the electrons are generated at cathode as it is negatively charged.
- Cathode ray tubes are the vacuum tubes that are fixed with the phosphor screen and it accelerates, modulates and also deflects the electron beam onto the screen that appears as a spot and produces the image.
- When this electron beam strikes the screen which is coated with the material that produces fluorescence, the electrical signals appear as patterns or spots on the screen to get the images.
So, the correct answer is “Option A”.

Note: Note that the screen coated with the phosphor material acts as fluorescent and also phosphorescent screen and they are not manufactured now a day because of environmental problems as the glass tube in it has high lead content required for X-ray shielding and other reasons.