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06 Computer Awareness — Common Notes 🕒 Updated 2026-10-17
Common Notes SSC CGL · CHSL · Police · Bank · Railway Chapter 06

🌐 Internet, Web & E-mail

History of the internet, WWW, browsers, URL, IP and DNS, search engines, e-mail, cloud computing and new technologies.

📌 1. Internet & WWW

  • The Internet = a worldwide network of networks, using the TCP/IP protocol.
  • It began as ARPANET (1969, US Department of Defense). TCP/IP — Vint Cerf and Bob Kahn.
  • Public internet in India: 15 August 1995, by VSNL.
  • WWW = a system of hyperlinked web pages on the internet; Tim Berners-Lee, CERN (1989). He also made the first browser (WorldWideWeb).
  • Intranet = an organisation's private network; extranet = limited access for outside partners.
TermMeaning
Web page / WebsiteOne page / a group of related pages
Home pageFirst page of a website
HyperlinkLink to another page
Web browserSoftware to view web pages — Chrome, Firefox, Edge, Safari
Web serverComputer that stores and serves web pages
Search engineGoogle, Bing, Yahoo, DuckDuckGo
CookiesSmall files stored in the browser by websites
BookmarkSaving a favourite page address
Upload / DownloadSending to a server / receiving from a server
⚠️ Exam Traps:
  • Internet ≠ WWW — the WWW is one service that runs on the internet.
  • Google is a search engine; Chrome is the browser.

📌 2. URL, IP & DNS

URL (Uniform Resource Locator) = address of a web resource. Example: https://www.example.com/notes/page.html → protocol (https) + domain (www.example.com) + path.

DomainMeaning
.comCommercial
.orgOrganisation
.eduEducation
.gov / .gov.inGovernment
.netNetwork
.milMilitary
.in / .uk / .jpCountry code (ccTLD)
  • IP address = numeric address of each device on a network. IPv4 = 32-bit (e.g. 192.168.1.1); IPv6 = 128-bit (hexadecimal).
  • DNS (Domain Name System) converts domain names into IP addresses — the "phone book" of the internet.
  • ISP = Internet Service Provider (Jio, Airtel, BSNL). MAC address = 48-bit hardware address of a network card.
  • HTTP = protocol for web pages; HTTPS = encrypted with SSL/TLS, secure (padlock icon).
⚠️ Exam Traps:
  • IPv4 = 32-bit, IPv6 = 128-bit, MAC = 48-bit.
  • Domain name → IP is done by DNS, not DHCP (DHCP assigns IP addresses).

📌 3. E-mail

  • The first network e-mail was sent by Ray Tomlinson (1971); he chose the @ sign.
  • E-mail address: username@domain, e.g. ravi@gmail.com.
  • CC = carbon copy (visible to all); BCC = blind carbon copy (hidden from other recipients).
  • SMTP = sending mail; POP3 and IMAP = receiving mail. Spam = unwanted bulk mail. Attachment = attached file.
  • Inbox = received; Outbox = waiting to be sent; Sent = already sent; Drafts = saved unfinished mails.
⚠️ Exam Traps:
  • Addresses in BCC are not shown to other recipients.
  • Sending protocol: SMTP; receiving: POP3/IMAP.

📌 4. Cloud & New Technologies

TechnologyMeaning
Cloud ComputingServers, storage, software rented over the internet — SaaS (Gmail), PaaS, IaaS (AWS)
IoT (Internet of Things)Everyday objects connected to the internet — smart bulbs, smart meters
AI / Machine LearningMachines learning and deciding — chatbots, face recognition
BlockchainDistributed, tamper-resistant digital ledger — Bitcoin
Big DataAnalysis of extremely large data sets
AR / VRAugmented Reality (digital layer over the real view) / Virtual Reality (fully virtual world)
5GFifth-generation mobile network; launched in India on 1 October 2022
⚠️ Exam Traps:
  • Gmail is a SaaS example; AWS EC2 is IaaS.

📌 5. Practice MCQs

📝 Practice MCQs (prepared by SF Prep — not PYQs)
Q1. The internet started from which network? Practice
(A) NSFNET
(B) ARPANET
(C) ETHERNET
(D) NICNET
Correct answer: (B)
ARPANET (1969) was a US Department of Defense project.
Q2. Who invented the World Wide Web? Practice
(A) Vint Cerf
(B) Ray Tomlinson
(C) Tim Berners-Lee
(D) Bill Gates
Correct answer: (C)
Tim Berners-Lee proposed the WWW at CERN in 1989.
Q3. When did public internet service start in India? Practice
(A) 1 April 2000
(B) 26 January 1991
(C) 15 August 1998
(D) 15 August 1995
Correct answer: (D)
VSNL launched the service on 15 August 1995.
Q4. What converts a domain name into an IP address? Practice
(A) DNS
(B) DHCP
(C) FTP
(D) SMTP
Correct answer: (A)
DNS = Domain Name System.
Q5. An IPv4 address is how many bits long? Practice
(A) 16
(B) 32
(C) 64
(D) 128
Correct answer: (B)
IPv4 = 32-bit (four parts, e.g. 192.168.0.1); IPv6 = 128-bit.
Q6. An IPv6 address is how many bits long? Practice
(A) 32
(B) 64
(C) 128
(D) 256
Correct answer: (C)
IPv6 = 128-bit, written in hexadecimal.
Q7. The full form of URL is: Practice
(A) Unique Resource Locator
(B) Universal Resource Link
(C) Uniform Reference Locator
(D) Uniform Resource Locator
Correct answer: (D)
A URL is the complete address of a web resource.
Q8. The ".edu" domain is usually related to: Practice
(A) Education
(B) Government
(C) Commerce
(D) Military
Correct answer: (A)
.edu = educational institutions; .gov = government; .mil = military.
Q9. A padlock icon on a web page indicates which protocol? Practice
(A) HTTP
(B) HTTPS
(C) FTP
(D) Telnet
Correct answer: (B)
HTTPS encrypts data with SSL/TLS.
Q10. Which of these is NOT a web browser? Practice
(A) Chrome
(B) Firefox
(C) Google
(D) Safari
Correct answer: (C)
Google is a search engine (and company); Chrome is its browser.
Q11. Which protocol is used to send e-mail? Practice
(A) POP3
(B) IMAP
(C) HTTP
(D) SMTP
Correct answer: (D)
SMTP = Simple Mail Transfer Protocol (send); POP3/IMAP = receive.
Q12. Which e-mail option hides a recipient's address from other recipients? Practice
(A) BCC
(B) CC
(C) To
(D) Reply
Correct answer: (A)
BCC = blind carbon copy.
Q13. Who sent the first network e-mail? Practice
(A) Tim Berners-Lee
(B) Ray Tomlinson
(C) Vint Cerf
(D) Larry Page
Correct answer: (B)
Ray Tomlinson in 1971 on ARPANET; he chose the @ sign.
Q14. Unwanted bulk e-mail is called: Practice
(A) Cookie
(B) Draft
(C) Spam
(D) Attachment
Correct answer: (C)
Spam = unwanted advertising/fraud mails.
Q15. A private network of an organisation that uses internet technology is called: Practice
(A) Extranet
(B) WAN
(C) Internet
(D) Intranet
Correct answer: (D)
An intranet is only for the organisation's staff.
Q16. Small text files stored in the browser by websites are called: Practice
(A) Cookies
(B) Bookmarks
(C) Plug-ins
(D) Cache
Correct answer: (A)
Cookies remember logins and preferences.
Q17. Gmail is an example of which cloud service model? Practice
(A) IaaS
(B) SaaS
(C) PaaS
(D) DaaS
Correct answer: (B)
SaaS = software as a service — software used directly in the browser.
Q18. Connecting objects like smart bulbs and smart meters to the internet is called: Practice
(A) Big Data
(B) Blockchain
(C) IoT
(D) VR
Correct answer: (C)
IoT = Internet of Things.
Q19. Cryptocurrencies like Bitcoin are based on which technology? Practice
(A) Bluetooth
(B) Cloud
(C) AR
(D) Blockchain
Correct answer: (D)
Blockchain is a distributed, tamper-resistant ledger.
Q20. When were 5G services formally launched in India? Practice
(A) 1 October 2022
(B) 15 August 2021
(C) 26 January 2023
(D) 1 April 2022
Correct answer: (A)
The Prime Minister launched 5G on 1 October 2022 at the India Mobile Congress.

📝 Practice questions

Computer Awareness — Practice MCQs (Bilingual) Ch 6: Internet, Web & E-mail | इंटरनेट व ईमेल
📝 Test this chapter Practice questions

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