Grade 9|| Information and Communication Technology|| Notes

1. Introduction to ICT in Modern Age

• Definition: ICT is the use of electronic devices (computers, mobiles, satellites) to store, process, and communicate information (sound, text, images, videos) quickly across the world.
• Examples from News:
  • Expansion of telecommunication in rural Jajarkot.
  • Launch of NepaliSat-1 (Nepal's first satellite).
  • Use of satellite radio collars on elephants for tracking.
  • Changes in TV viewing via internet (e.g., Nepal TV free-to-air, IPTV).
• Activity 13.1: Search news headlines online and discuss technology type, uses, advantages.

2. Artificial Satellites

• What are Satellites?: Man-made objects orbiting Earth. Launched by rockets, revolve without extra fuel (no air friction), powered by solar energy.
• First Satellite: Sputnik-1 (USSR, 1957).
• Communication: Uplink (Earth → satellite), Downlink (satellite → Earth) using microwaves.

Sub-Components: Types of Orbits

• LEO (Low Earth Orbit): 180–2,000 km
  • Short revolution time (e.g., 90 min).
  • Uses: Earth observation, photos, scientific research.
  • Example: International Space Station (ISS) at 408 km.
• MEO (Medium Earth Orbit): 2,000–35,786 km
  • Revolution ~12 hours.
  • Uses: Navigation (GPS – 24 satellites for global location).
  • Example: GPS system.
• GEO (Geostationary Orbit): 35,786 km (above equator)
  • Revolution matches Earth's rotation (23h 56min) → appears stationary.
  • Uses: TV, telephone, mobile, internet broadcasting.
• Activity 13.2: Fill table on orbit characteristics, purpose, examples.

Nepal's Satellite: NepaliSat-1

• Details: Nanosatellite (1.3 kg cube), built by Nepali students (Aavash Maskey, Hariram Shrestha) at Kyutech University, Japan with NAST support.
• Launch: April 2019 from USA, released from ISS in June 2019.
• Orbit: ~400 km (LEO), revolution 90 min, visible 6-10 min over Nepal.
• Purpose: Take photos of Nepal's geography, forests, glaciers, mountains, roads.
• Activity 13.3: Discuss NepaliSat-1 using audio-visual materials.

3. Use of ICT Devices (Activity 13.4 – Daily Life Tools)

• Magazine: Printed knowledge, news.
• Radio: Fast audio broadcasting (news, songs, stories).
• Television: Visual programs, live events.
• Telephone/Fax: Voice calls, document transfer.
• Mobile Phone: Calls, messages, internet.
• Wi-Fi: Wireless networking.
• Email: Fast text + files.
• Internet: Search, online services.
• GPS: Location finding, navigation.

4. Telecommunication

• Definition: Transfer of signals (sound, picture, data) using wire, optical fiber, waves, satellites.
• Examples: Telephone, fax, mobile, radio/TV broadcasting, internet.

Working Principle (Activity 13.7)

• Three Parts:
  • Transmitter: Converts input (voice/image) to signals.
  • Channel: Wire, radio waves, microwave, optical fiber.
  • Receiver: Converts signals back to original form.

Modulation & Demodulation

• Why Modulation?: Information signals weak → mix with strong carrier waves (radio waves).
• Types:
  • AM (Amplitude Modulation): Changes wave height (amplitude).
    • Long/medium waves, reflects from ionosphere → long distance.
    • Frequency: 535–1705 kHz (e.g., Radio Nepal 792 kHz).
    • Clearer at night.
  • FM (Frequency Modulation): Changes wave frequency.
    • High frequency, no reflection → limited distance but clear sound.
    • Frequency: 88–108 MHz (e.g., Radio Nepal 100 MHz).
• Activity 13.8 & 13.9: Investigate radio waves, fill tables on modulation.

5. Internet as Modern Communication Tool (Activity 13.10)

• Changes Due to Internet:
  • Letters/Fax → Email/Gmail.
  • Cable TV → IPTV/online streaming.
  • Audio calls → Video calls (cheap).
  • Paper news → Online news (instant).
• Activity 13.11: Step-by-step create Gmail account and send email.

6. Using Internet for Study Materials (Activity 13.12)

• Search Operators:
  • site: → specific website.
  • inurl: → word in URL.
  • filetype: → file type (e.g., pptx, docx, pdf).
  • OR, AND, quotes for exact phrase.
• Authenticity: Check .edu/.gov/.org sites, date, copyright.
• Copyright: Mention source if used.

7. Online Security Measures (Activity 13.13)

• Online Privacy: Check HTTPS, avoid unknown links.
• Cyberbullying: Don't accept strangers, report harassment.
• Digital Footprint: Online actions permanent (even deleted).
• Firewall: Blocks unsafe signals (turn on in computer).
• Antivirus: Removes viruses (e.g., Windows Defender).
• Activity 13.14: Observe firewall/antivirus, discuss cyber-attacks.
• Project Work: Study cybercrimes in Nepal (ATM hacking, phishing, etc.).