Class 9 Computer — Hardware Important Questions with Answers (Long answers)

A computer takes data through input devices (keyboard, mouse, scanner, mic). The CPU’s control unit and ALU process it using registers and cache. RAM holds working data; ROM holds start-up code. Results go to output devices (monitor, printer, speaker). Secondary storage keeps files after shutdown. UPS protects the process from sudden power loss. Class 9 answers should name parts and the direction of data, not invent extra chips. Example: typing an essay (input), editing in RAM (process), saving on disk (storage), printing (output).

Keep liquids away, do not eat at the keyboard, use UPS/stabiliser if provided, do not block CPU fans, insert USB carefully, shut down before unplugging, cover webcams for privacy, report loose sockets to the teacher. Dust and humidity harm ports. Pendrives should be scanned. These are maintenance habits, not extra theory chips. Good care is cheaper than a new machine.

Inkjet: colour photos, cheaper machine, costlier per page, slower. Laser: fast office text, toner, common in school offices. Dot-matrix: impact, multi-part bills, noisy, still seen in some offices. Plotters draw wide graphics. Choose by speed, colour need and running cost. All are output. Spooling is the OS holding print jobs — a line is enough if asked.