Quick summary
Devices that give data to the computer are input devices. Devices that show us the computer's result are output devices. Devices that keep data safely for later are storage devices (साठवण उपकरणे). Some devices do both input and output, for example a touch screen.
Key points
- The keyboard and mouse are the most common input devices.
- The monitor and printer are the main output devices.
- A result shown on the screen is a soft copy.
- A result printed on paper is a hard copy.
- Banks use MICR to read cheques.
- OMR checks the filled bubbles on answer sheets.
- OCR reads printed text and turns it into editable text.
- A touch screen is both an input and an output device.
- Backspace erases the character to the left of the cursor; Delete erases the one to the right.
- An SSD is faster than an HDD because it has no moving parts.
Keyboard and mouse
Groups of keys
| Group | Example / use |
|---|---|
| Alphanumeric keys | A to Z, 0 to 9 |
| Function keys | F1 to F12; for example F1 = Help |
| Numeric keypad | Number keys on the right; easy for calculations |
| Arrow / navigation keys | ↑ ↓ ← →, Home, End, Page Up, Page Down |
| Special keys | Ctrl, Alt, Shift, Esc, Tab, Caps Lock, Enter |
- Caps Lock – types all letters in capitals.
- Shift – hold it to type one capital letter or the upper symbol on a key.
- Enter – starts a new line or gives a command.
- Esc – cancels the current action.
Mouse actions
- Left click – select something.
- Double click – open a file or program.
- Right click – open a list of options (context menu).
- Drag – hold the button and move an item to another place.
- Scroll – turn the wheel to move the page up or down.
Other devices
- Input: scanner (puts a paper image into the computer), webcam (video calls), microphone (sound), barcode reader (product codes in shops), biometric scanner (fingerprints, for example attendance or Aadhaar verification).
- Output: monitor (LED/LCD), speakers, headphones, projector (shows the screen on a big wall or screen).
- Types of printers: inkjet (sprays ink, home use), laser (fast and sharp, for offices), dot-matrix (strikes pins on a ribbon, noisy, used for bills).
| Device | Type |
|---|---|
| Keyboard | Input |
| Mouse | Input |
| Scanner | Input |
| Microphone | Input |
| Monitor | Output |
| Printer | Output |
| Speaker | Output |
| Projector | Output |
| Touch screen | Both input and output |
Storage devices
- Hard disk (HDD) – large storage inside the computer; data is on spinning disks.
- SSD (Solid State Drive) – no moving parts; very fast.
- Pen drive – small portable device that connects by USB.
- Memory card – used in mobiles and cameras.
- CD / DVD – optical discs; a DVD holds more data than a CD.
- Cloud storage – data kept on internet servers, for example Google Drive, OneDrive.
Important terms
- Cursor – the blinking line that shows where your typing will appear.
- MICR – Magnetic Ink Character Recognition (for cheques).
- OMR – Optical Mark Recognition (marks on answer sheets).
- OCR – Optical Character Recognition (reading printed letters).
- Soft copy – output on the screen or as a file.
- Hard copy – output printed on paper.
Practice questions (with answers)
Q1. Which technology do banks use to read cheques?
- (A) OMR
- (B) MICR
- (C) Webcam
- (D) Projector
Answer: (B) MICR – it reads the numbers printed in magnetic ink on cheques.
Q2. Which of these is both an input and an output device?
- (A) Printer
- (B) Keyboard
- (C) Speaker
- (D) Touch screen
Answer: (D) Touch screen – it takes your touch and also shows the picture.
Q3. What is a result printed on paper called?
- (A) Hard copy
- (B) Soft copy
- (C) Backup
- (D) Cursor
Answer: (A) Hard copy – the result on screen is a soft copy.
Q4. Which key erases the character to the left of the cursor?
- (A) Delete
- (B) Tab
- (C) Backspace
- (D) Esc
Answer: (C) Backspace – Delete erases the character to the right.
Q5. Which printer prints by striking pins and is noisy?
- (A) Laser
- (B) Inkjet
- (C) Projector
- (D) Dot-matrix
Answer: (D) Dot-matrix – it is an impact printer.
Exam tip
Remember what MICR, OMR and OCR are used for, and that a touch screen is both input and output.