Computer Science
Discuss the following devices:
(a) Light Pen
(b) Graphic Tablet
(c) CD-ROM
(d) DVD
Answer
(a) Light Pen — A light pen is a pointing device that can be used to select anything on the computer screen by simply pointing at it or for drawing figures directly on the screen. It consists of a photocell mounted on a pen-shaped tube called stylus. It is capable of sensing a position on the screen when its tip touches the screen. Clicking is performed by pressing the pen on the screen. A light pen is mostly used by engineers, architects or designers.
(b) Graphic Tablet — A graphic tablet is an input device with a touch-sensitive surface that allows users to create digital art and designs. It comes with a stylus that mimics traditional drawing tools. Graphic tablets connect to computers via USB or Bluetooth, facilitating precise digital artwork, photo editing, 3D modelling, and handwriting.
(c) CD-ROM — It is a thin optical disc which is commonly used to store audio and video data. The capacity of a standard 120 mm CD is 700 MB. Originally, CD-ROM drives had transfer rate of only 150 KB/s which was very low. The latest CD-ROM drives can transfer up to 10800 KB/sec.
(d) DVD — Digital Versatile Disc or Digital Video Disc is an optical disc storage device. It can be recorded on one or both sides. Its capacity may range from 4.7 GB to 17.08 GB.