Class 11 Computer Science (SLO Based) Notes For the Examination 2024 and onwards under the Federal Board of Intermediate and Secondary Education (FBISE), Islamabad, Punjab Boards, Rawalpindi, Lahore, Karachi board, etc., and All other boards in Pakistan and abroad.
Unit-1
Unit-1
"Introduction to Computers"
************************************
************************************
1. Brief/Long Response Questions and Answers:
Q3. What is Computer Hardware? Explain in detail.
Ans:
Computer Hardware:
Physical components which can be seen and touched. It Included input devices, output devices, memory, processing, storage etc.
input devices
Input devices provide data and instructions to the computer. It accepts data in human-readable form and converts it into machine-readable form.
Examples: keyboard, mouse, microphone, etc.
Keyboard:
- It is used to input data in the form of text.
- A keyboard has keys or buttons on it.
- It converts keys pressed to electric signals in digital form.
- It has alphabet keys, numeric keys, function keys, and special keys.
Pointing Input Devices:
- Used to control the movement of the cursor on the screen.
Mouse:
Trackball:
- It has a ball on top that is rolled with fingers.
- It is stationary on the surface.
- Also has buttons like a mouse performing similar operations.
Joystick:
- It is used for playing games.
- t has a stick and buttons on it.
- The movement of objects on the screen is controlled by tilting the stick.
Touch Screen:
- Both Input and output devices.
- Pressure-sensitive screen.
- A user interacts with the computer by touching the icons or text on the screen using fingers or a stylus.
- Mostly popular in smartphones, PDAs, navigators, tablet PCs, etc.
Light Pen:
- Similar to a pen having a photo sensor at its tip.
- It is used for pointing and drawing on the screen.
- Provides better control and accuracy than a mouse and touch screen.
- Used for designing and engineering purposes.
Touch Pad:
- It is a touch-sensitive surface.
- Sense the movement of fingers and control the pointer movement on the screen Accordingly.
- Used in laptop computers as an alternative to mouse.
- Also has two buttons like a mouse below it.
Microphone:
- It is used for voice input.
- It converts audio signals into electrical signals.
- A sound card then converts electric signals into digital form.
Digital Camera:
- It captures
- pictures and stores them in digital form.
- It has a memory card for storage.
- The images captured can be downloaded to the computer.
- Some digital cameras have LCD to view images, edit or delete them.
Scanners:
It reads text or images from paper and stores them in a computer in digital form.
Types of scanners:
- Handheld scanner
- Flatbed scanner
- Barcode reader
Handheld scanner:
- It is a handheld device that is moved over the image to be scanned.
- It must be moved with uniform speed to provide image without distortion.
- They are slower than flatbed scanners.
- It can scan entire images at a time.
- The image is placed face down on the glass and covered with a lid.
- It scans bar code or UPC (Universal Product Code) on products.
- Barcode has information about the product like expiry date, price, etc.
- This information is given to computers for generating bills which makes faster checkouts.
Magnetic Strip Card Reader:
- It reads information on a magnetic strip located on a plastic card.
- Information is stored in the form of magnetized spots.
- Information can be read by swiping the cards on the reader.
Output Devices:
Output devices display useful information.
Types of Output Devices:
Softcopy output: it is displayed on a screen in the form of text, images, video, etc.
Hardcopy output: it is in printed form on paper by a printer or plotter.
Sound output: output generated through speakers in the form of sound.
Monitor:
- Also called VDU( Video Display Unit)
- It produces soft copy output. (text, graphics, video, animations, etc.)
Features:
- Size: monitor varies in size from 15 to 21 inches.
- Colour: monitor can be black and white or RGB (colored).
- Pixel: stands for picture element. It is a small dot on the monitor forming an image.
- Resolution: numbers of pixels per square inch. Higher the resolution better the image quality.
- Dot pitch. Distance between two pixels on the screen. Lesser dot pitch means higher resolution.
Types of monitor:
CRT, LCD, LED, etc.
CRT (Cathode Ray Tube) Monitors.
- Similar to standard television sets.
- Heavier and consume more power.
- It is a vacuum tube having an electron gun and a phosphor-coated screen.
- An electron gun sprays a beam of electrons which glows the phosphor-coated screen when striking it.
- Colored monitors have three electron guns and phosphor atoms (Red, Green, and Blue) RGB.
- The remaining colors are produced by the combination of Red, green, and blue.
LCD (Liquid Crystal Display):
- It is thin and lightweight.
- They have better resolution and emit less radiation than CRT.
- They are portable, less expensive, reliable, and less harmful to the eyes than CRT.
- It has a fluid-like substance called liquid crystal between two sheets.
- These molecules are lined up on the screen and have two states.
- either they allow or block the light to produce images on screen.
- They are used in, laptops, monitors, phones, clocks, etc.
LED (Light Emitting Diode):
- It uses LED (Light Emitting Diode) as pixels.
- Lighter in weight and consume less power than LCD.
- Better resolution and emit less radiation.
- Long-lasting and reliable.
- Expensive than other monitors
Printers:
- Produce hardcopy output.
- Connected to computers through parallel or USB ports.
- Print quality, print speed, printing graphics.
Types of Printers:
- Impact printers
- Non-impact printers
Impact printers:
- Work like a typewriter.
- Image is produced when the print head strikes against the paper.
- Impact printers have low print quality
- they produce a lot of noise.
- They are slow and poor ability to print graphics.
Dot matrix Printers:
- The dot matrix has 9 to 24 pins on its print head.
- Its print quality depends upon the number of pins.
- Not very popular nowadays.
Chain printers:
- They are line printers. (can print one line at a time).
- It contains a character on a chain that moves very fast.
- The image is produced when a set of hammers strike against an ink ribbon on paper.
- They produce images without striking the paper.
- They are fast (print an entire page at a time).
- Better print quality than impact
- Produce very less noise while printing.
- Expensive than impact printers.
- Better ability to print graphics.
Laser printers:
- Print technology is similar to photocopiers.
- They are very fast and silent.
- Print an entire page at a time.
- Print quality is very high.
- Also, print colored graphics.
Inkjet printers:
- They produce images by spraying tiny drops on ink on paper.
- Less expensive and slower than laser printers.
- Print quality is also less than laser printers.
- Can produce colored prints cheaper than laser printers.
Plotters:
- Produce large-scale hardcopy output.
- Used in architectural drawings, maps, graphs, civil engineering drawings, and panaflexes.
Examples: flatbed plotters and drum plotters.
Flatbed plotters:
• Paper is spread and fixed n rectangular flat surface.
• It has a mechanical arm holding different colored pens.
• Which is moved on the surface to draw the image.
Drum Plotter:
- It has a rotating drum.
- The sheet is fed from one side of the drum.
- The drum rotates to move the paper.
- It produces large-size panaflexes.
Speakers:
- Produce audio output.
- Attached to the sound card on the motherboard.
- Convers electric signals in sound form.
************************************
Please Select from below 👇👇
Unit-1 (Important Short Q/A)
************************************
************************************
************************************
Shortcut Links For:
1. 5th Class All Subjects Notes
2. 8th Class All Subjects Notes
1. Website for School and College Level Physics
2. Website for School and College Level Mathematics
3. Website for Single National Curriculum Pakistan - All Subjects Notes
© 2023 & onwards Academic Skills and Knowledge (ASK)
Note: Write me in the comments box below for any query and also Share this information with your class-fellows and friends.
0 Comments
Start Tuition (in Pakistan or Abroad) from Experienced Online Teachers.
Contact WhatsApp for tutoring and Assignment help on +923339719149