Question

The property of cathode rays used in the monitor of a computer is:
A) High velocity of the rays
B) High ionization power of the rays
C) The property to cause fluorescence
D) Rectilinear propagation

Answer 1

Cathode rays are responsible for the formation of images on a TV screen and on the monitor of a computer screen. Property of emission of light which is absorbed by electromagnetic radiation is used by the cathode rays for the monitor of the computer or TV displays. Using the above hint we will select the most appropriate option.

Complete step by step solution:
First we will discuss the cathode ray tube from which cathode rays are generated and then properties of the cathode rays.
Cathode ray tube is a vacuum tube which contains one or more electron guns and a phosphorescent screen for the purpose of displaying images. Cathode ray tube modulates, deflects, and accelerates the beam of electrons in such a manner that it creates images on the screen of the monitor. In coloured devices an image is produced on the screen by controlling the intensity of all the three primary colours (red blue and green).
When a beam of electrons is released from the cathode ray tube the cathode of the tube gets heated up like a filament which is in vacuum inside a glass tube. These generated electrons from the cathode of the tube reach to the anode of the tube because of attraction property, these electrons then get accumulated on the phosphor screen (which glows when illuminated by electron beam); this process is called Fluorescence.
Thus cathode rays use the property of fluorescence.

Option (C) is correct.

Note: Cathode ray tube has one of the most useful applications which includes; used in the oscilloscope for the formation of graphs and other useful images. An oscilloscope is an electronic device which measures the changes in electrical voltage by plotting against x axis and y axis.