CG OLD NOV/DEC 2017 PAPER SOLUTION BY- S.K. SHELKE SECTION A QUESTION.1 a) With suitable diagram explain the construction and working of CRT. ANS: Computer graphics is an art of drawing pictures on computer screens with the help of programming. It involves computations, creation, and manipulation of data. In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of images. Cathode Ray Tube The primary output device in a graphical system is the video monitor. The main element of a video monitor is the Cathode Ray Tube (CRT), shown in the following illustration. The operation of CRT is very simple − ● The electron gun emits a beam of electrons (cathode rays). ● The electron beam passes through focusing and deflection systems that direct it towards specified positions on the phosphor-coated screen. ● When the beam hits the screen, the phosphor emits a small spot of light at each position contacted by the electron beam. ● It redraws the picture by directing the electron beam back over the same screen points quickly. There are two ways (Random scan and Raster scan) by which we can display an object on the screen.