About this quiz
Input and output devices, printers and ports.
This Lok Sewa practice set has 51 multiple-choice questions (Subject: Computer Knowledge · For: Kharidar, Nayab Subba, Computer Operator · Level: Medium). Take the quiz above first; after that, use the study list below to revise every question with its correct answer and a short explanation.
Study list: all 51 questions with answers and explanations
Which of these is an input device?
- A) Monitor
- B) Printer
- C) Scanner ✔
- D) Speaker
Why: A scanner is an input device: it reads a paper document or photo and sends it into the computer as a digital image.
Which of these is an output device?
- A) Keyboard
- B) Plotter ✔
- C) Mouse
- D) Joystick
Why: A plotter is an output device: it takes data from the computer and draws large prints such as maps and engineering drawings.
Which device works as both input and output?
- A) Touchscreen ✔
- B) Scanner
- C) Printer
- D) Microphone
Why: A touchscreen is both: it displays output like a monitor and takes input when you touch it.
Who invented the computer mouse?
- A) Charles Babbage
- B) Douglas Engelbart ✔
- C) Bill Gates
- D) Tim Berners-Lee
Why: Douglas Engelbart invented the mouse in the 1960s at Stanford Research Institute. The first one had a wooden body.
MICR technology is mainly used in:
- A) Hospitals
- B) Banks for cheques ✔
- C) Schools for attendance
- D) Shops for prices
Why: MICR (Magnetic Ink Character Recognition) is used by banks to read the special magnetic-ink numbers printed at the bottom of cheques.
Multiple-choice answer sheets are checked using:
- A) OCR
- B) MICR
- C) OMR ✔
- D) Barcode reader
Why: OMR (Optical Mark Recognition) detects filled bubbles or marks on answer sheets, so objective exams can be checked quickly.
Which device converts printed text into editable text?
- A) OMR
- B) OCR ✔
- C) MICR
- D) Plotter
Why: OCR (Optical Character Recognition) recognises printed letters in a scanned image and turns them into text you can edit.
A printed copy of output is called:
- A) Soft copy
- B) Hard copy ✔
- C) Backup
- D) Draft
Why: Output printed on paper is a hard copy. Output shown on screen or saved as a file is a soft copy.
The tiny dots that make up a screen image are called:
- A) Bits
- B) Pixels ✔
- C) Bytes
- D) Fonts
Why: Pixels (picture elements) are the tiny dots that make up a screen image. More pixels mean a sharper picture.
Which printer uses toner powder?
- A) Inkjet
- B) Dot matrix
- C) Laser ✔
- D) Thermal
Why: A laser printer uses toner powder: a laser draws the page on a drum, the toner sticks to it and heat fuses it onto paper.
Which is an impact printer?
- A) Laser
- B) Inkjet
- C) Dot matrix ✔
- D) Thermal
Why: A dot matrix printer is an impact printer: tiny pins strike an inked ribbon against the paper. It is noisy but can print carbon copies.
Shop receipts and ATM slips are usually printed by a:
- A) Thermal printer ✔
- B) Laser printer
- C) Daisy wheel printer
- D) Plotter
Why: Thermal printers print receipts and ATM slips by heating special heat-sensitive paper, with no ink or toner.
Print quality is measured in:
- A) ppm
- B) cps
- C) dpi ✔
- D) rpm
Why: Print quality is measured in dpi (dots per inch). A higher dpi gives finer, sharper print.
Laser printer speed is usually measured in:
- A) Pages per minute ✔
- B) Characters per second
- C) Lines per hour
- D) Dots per inch
Why: Laser printer speed is measured in ppm (pages per minute). Dot matrix speed is often given in cps (characters per second).
Large engineering drawings and maps are printed using a:
- A) Plotter ✔
- B) Projector
- C) Dot matrix printer
- D) Scanner
Why: A plotter prints large engineering drawings, maps and architectural plans with precise lines.
USB stands for:
- A) Universal Serial Bus ✔
- B) Unique System Board
- C) United Serial Bus
- D) Universal System Bridge
Why: USB stands for Universal Serial Bus, a standard port for connecting devices such as pen drives, keyboards and printers.
Which port carries both high-definition video and audio?
- A) VGA
- B) PS/2
- C) HDMI ✔
- D) RJ-11
Why: HDMI (High-Definition Multimedia Interface) carries digital HD video and audio together in one cable.
An Ethernet (LAN) cable connects to which port?
- A) RJ-11
- B) RJ-45 ✔
- C) VGA
- D) PS/2
Why: An Ethernet (LAN) cable uses the RJ-45 connector. The smaller RJ-11 is used for telephone lines.
The common keyboard layout is called:
- A) AZERTY
- B) QWERTY ✔
- C) DVORAK
- D) ABCDEF
Why: The common layout is QWERTY, named after the first six letters on the top letter row.
Which device is mainly used for playing games?
- A) Light pen
- B) Joystick ✔
- C) Scanner
- D) Plotter
Why: A joystick is mainly used for games and flight simulators, to control movement in different directions.
Which device is used to input printed text into a computer as an image?
- A) Scanner ✔
- B) Printer
- C) Speaker
- D) Plotter
Why: A scanner digitises printed pages as images. OCR software can then turn that image into editable text.
A device that reads marks on answer sheets is:
- A) OCR
- B) OMR ✔
- C) MICR
- D) Barcode printer
Why: An OMR (Optical Mark Reader) reads pencil or pen marks on answer sheets and forms.
MICR is mainly used in:
- A) Schools for attendance
- B) Hospitals for X-rays
- C) Banks to read cheques ✔
- D) Shops for weighing
Why: MICR (Magnetic Ink Character Recognition) is used in banks to read cheque numbers printed in magnetic ink quickly and securely.
OCR converts:
- A) Sound into text
- B) Video into images
- C) Text into speech
- D) Printed text into editable text ✔
Why: OCR (Optical Character Recognition) converts printed or typed text in an image into editable, searchable text.
Which is both an input and output device?
- A) Touchscreen ✔
- B) Keyboard
- C) Mouse
- D) Monitor
Why: A touchscreen is both an input and output device: it shows the display and senses your touch.
A light pen is a:
- A) Output device
- B) Pointing input device ✔
- C) Storage device
- D) Printer
Why: A light pen is a pointing input device: you touch the screen with it to select items or draw.
Joysticks are mostly used for:
- A) Printing
- B) Scanning documents
- C) Games and simulators ✔
- D) Storing data
Why: Joysticks are mostly used for games and simulators, where they control movement such as steering a plane.
A barcode reader is an example of:
- A) Output device
- B) Storage device
- C) Processing device
- D) Input device ✔
Why: A barcode reader is an input device: it reads the barcode on a product and sends the code into the computer, as in shop billing.
A microphone is a/an:
- A) Input device ✔
- B) Output device
- C) Storage device
- D) Processing unit
Why: A microphone is an input device: it captures sound and sends it into the computer.
A webcam is a/an:
- A) Output device
- B) Input device ✔
- C) Storage device
- D) Printer
Why: A webcam is an input device: it captures images and video for the computer, for example for video calls.
The most common output device is the:
- A) Keyboard
- B) Scanner
- C) Monitor ✔
- D) Mouse
Why: The monitor is the most common output device: it displays text, pictures and video as soft copy.
Screen resolution is measured in:
- A) Dots per minute
- B) Hertz only
- C) Bytes
- D) Pixels ✔
Why: Screen resolution is measured in pixels, given as width × height, for example 1920 × 1080.
LCD stands for:
- A) Liquid Crystal Display ✔
- B) Light Crystal Diode
- C) Liquid Colour Device
- D) Laser Crystal Display
Why: LCD stands for Liquid Crystal Display, a flat screen that uses liquid crystals to form the picture.
LED in monitors stands for:
- A) Liquid Electronic Display
- B) Light Emitting Diode ✔
- C) Laser Emitting Device
- D) Light Energy Display
Why: LED stands for Light Emitting Diode. LED monitors use LEDs as the backlight, making them thinner and more power-efficient.
CRT monitors use a:
- A) Liquid crystal
- B) Laser beam
- C) Cathode Ray Tube ✔
- D) Plasma gas only
Why: CRT monitors use a Cathode Ray Tube, a bulky glass tube that fires electrons at the screen. They were used before flat screens.
A printer that strikes an inked ribbon is an:
- A) Inkjet printer
- B) Laser printer
- C) Thermal printer
- D) Impact printer ✔
Why: A printer that strikes an inked ribbon is an impact printer, such as a dot matrix printer.
Which printer sprays tiny drops of ink?
- A) Inkjet ✔
- B) Dot matrix
- C) Laser
- D) Daisy wheel
Why: An inkjet printer sprays tiny drops of liquid ink onto paper. It is a non-impact printer, good for colour prints.
Which printer uses toner?
- A) Inkjet printer
- B) Laser printer ✔
- C) Dot matrix printer
- D) Thermal printer
Why: A laser printer uses toner powder, which heat fuses onto the paper. It is fast and suits office printing.
Printer print quality is measured in:
- A) PPM
- B) RPM
- C) DPI ✔
- D) Hz
Why: Print quality is measured in DPI (dots per inch). A higher DPI means sharper text and images.
Printer speed is often measured in:
- A) DPI
- B) GB
- C) Hz
- D) PPM ✔
Why: Printer speed is often measured in PPM (pages per minute), especially for laser and inkjet printers.
A plotter is used to print:
- A) Large drawings and maps ✔
- B) Small receipts
- C) Sound
- D) Video
Why: A plotter prints large drawings and maps, such as engineering designs and building plans.
A speaker is a/an:
- A) Input device
- B) Output device ✔
- C) Storage device
- D) Processing device
Why: A speaker is an output device: it turns the computer's audio signal into sound.
A projector is a/an:
- A) Input device
- B) Storage device
- C) Output device ✔
- D) Network device
Why: A projector is an output device: it shows the computer's display on a large screen or wall.
HDMI carries:
- A) Both audio and video ✔
- B) Only audio
- C) Only power
- D) Only network data
Why: HDMI carries both digital audio and video in one cable, for example to a TV or projector.
VGA ports are used for:
- A) Network cable
- B) Analog video to monitors ✔
- C) Audio only
- D) Printer power
Why: VGA (Video Graphics Array) is an older port that sends analog video to monitors and projectors. It carries no audio.
The port used for a wired LAN cable is:
- A) RJ-11
- B) HDMI
- C) RJ-45 ✔
- D) VGA
Why: The RJ-45 port is used for a wired LAN (Ethernet) cable.
RJ-11 is commonly used for:
- A) Ethernet LAN
- B) Monitors
- C) Speakers
- D) Telephone lines ✔
Why: RJ-11 is the small jack used for telephone lines and dial-up or DSL modems.
A biometric device that reads fingerprints is a/an:
- A) Input device ✔
- B) Output device
- C) Printer
- D) Storage device
Why: A fingerprint reader is an input device: it captures fingerprint data, for example for office attendance.
A thermal printer is commonly used for:
- A) Large maps
- B) Receipts and tickets ✔
- C) Photo albums
- D) Engineering drawings
Why: Thermal printers are used for receipts and tickets, such as shop bills, ATM slips and bus tickets.
A device that converts a printed image or document into digital form is called a:
- A) Digitiser scanner ✔
- B) Plotter
- C) Speaker
- D) Projector
Why: A scanner (digitiser) converts a printed image or document into digital form that the computer can store.
Which of these is a pointing device used on laptops?
- A) Touchpad ✔
- B) Plotter
- C) Printer
- D) Webcam
Why: A touchpad is the pointing device on laptops: moving a finger on it moves the pointer, like a mouse.