3.  is a general-purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.

4. Input Process Storage Output

5. System Unit A typical desktop computer consists of a computer system unit a keyboard, a mouse, and a monitor. Monitor is an electronic visual display for computers. The monitor comprises the display device, circuitry and an enclosure.

6. System unit A typical desktop computer consists of a computer system unit, a keyboard, a mouse, and a monitor.

7. Monitor a display is an electronic visual display for computers The monitor comprises the display device, circuitry and an enclosure.

8. Keyboard  is a typewriter-style device, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter- style keyboards became the main input device for computers.

9. Mouse  is a pointing device that detects two-dimensional motion relative to a surface.  The one that control the movement of the cursor.

10. Optical Mouse  An optical mouse uses camera technology and digital processing to compare and track the position of the mouse, rather than a ball and rollers used on older devices

11. Mechanical Device is a computer mouse that contains a metal or rubber ball on its under side. When the ball is rolled in any direction, sensors inside the mouse detect this motion and move the on- screen mouse pointer in the same direction.

12. Automatic Voltage Regulator ( AVR ) is a device designed to regulate voltage automatically – that is, to take a fluctuating voltage level and it converts AC to DC.

13. is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or other information appliance.

15.  is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into human-readable form.

17. Hardware is the collection of physical elements that constitutes a computer system. Computer hardware is the physical parts or components of a computer, such as the monitor, mouse, keyboard, computer data storage, hard disk drive (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), and so on, all of which are physical objects that can be touched (that is, they are tangible). Software is any set of machine-readable instructions that directs a computer’s processor to perform specific operations. Computer software contrasts with computer hardware, which is the physical component of computers. meaning application software only. Software is stored in computer memory and is intangible, i.e. it cannot be touched.

18.  Children especially who are not using the computers in the right manner are at the most risk. There are several negative effect on children.  Children spend much time in playing games or social networking rather than their education and learning.  Children are becoming lazy and have lost the habit of manually referring to books or dictionary.  They like to spend much time on the computer rather than playing outdoor games.  Can get diseases on the computer.

19.  It reduces human laborious effort.  It provides us with extreme convenience in accessing and processing information, which was previously impossible.  Computer have made life easier and more convenient.

20.  Computers can help businesses by making their staff efficient and productive and also save their valuable time in any business or office.  There is a need for more computers in everyday life, in homes, schools and on the job.  Computer helping students get better grades in school, from help with homework over the internet to doing research for an essay at the local library.  Computers are now being used to help the blind with a voice synthesizer that tells them what they are typing or what they are trying to see on the screen.  Computers in law enforcement, today computers are being used in law enforcement to check records of people who are arrested for all types of crime, and to make sure that they are who they say they are.