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CBSE · Class 12 · Computer Science

Computer Networks

Standard difficulty · 20 questions · 40 marks · Time: 41 minutes

Name: Date: Score: ____ / 40

Show your working for Sections B and C. Answers are on the last page — try every question first!

Section A — Choose the correct answer8 × 1 = 8 marks
1.
The first network, which linked a few universities and research centres in 1969, was:
  1. the World Wide Web
  2. Ethernet
  3. NSFNET
  4. ARPANET
2.
What does a repeater do in a network?
  1. regenerates a weakened signal so it can travel further
  2. connects networks that use different protocols
  3. lets a computer join a wireless network
  4. sends the data only to the computer it is addressed to
3.
Which type of network is this: the computers in one office floor sharing a printer?
  1. MAN
  2. PAN
  3. LAN
  4. WAN
4.
How many cables (links) are needed to connect 4 computers in a ring topology?
  1. 4
  2. 3
  3. 5
  4. 6
5.
Which of these is a valid IPv4 address?
  1. 159.216.46.285
  2. 152.39.329.45
  3. 101.203.128.178
  4. 144.132.215.245.9
6.
In the URL http://mail.example.org/notes/chapter1.html, what is the domain name?
  1. mail.example.org
  2. /notes/chapter1.html
  3. http://mail.example.org
  4. http://mail.example.org/notes/chapter1.html
7.
Which describes the ring topology?
  1. each node is connected to two neighbours, forming a closed loop
  2. star networks joined in a hierarchy, branching from a root
  3. every node is connected to a central hub or switch
  4. every node is connected to every other node
8.
An address is 128 bits long. How many bytes is that?
  1. 16
  2. 128
  3. 8
  4. 32
Section B — Short answer8 × 2 = 16 marks
9.
What is a computer network? Give two of its advantages.
10.
Name the network device that (a) converts digital data to analog signals for a telephone or cable line, and back (b) lets a computer join a wireless network.
11.
Name the type of network (PAN, LAN, MAN or WAN): the computers of one school building.
12.
18 computers are to be connected. How many links are needed in (a) a mesh topology (b) a star topology with a central switch?
13.
For the URL https://maps.example.com/docs/report.pdf, write (a) the protocol (b) the domain name (c) the file path on the server.
14.
Is 222.254.337.17 a valid IPv4 address? Answer Yes or No.
15.
What kind of website does each top-level domain usually show: (a) .gov (b) .com?
16.
Name the topology in which (a) every node is connected to every other node (b) star networks joined in a hierarchy, branching from a root.
Section C — Word problems4 × 4 = 16 marks
17.
Describe the evolution of networking from ARPANET to the Internet.
18.
A school has four blocks: Junior (49 computers), Science (12 computers), Sports (25 computers), Library (38 computers). Junior is 71 m from Library, 107 m from Sports and 92 m from Science. (a) Which block should house the server, and why? (b) Suggest a topology and draw the layout in words. (c) Where would a repeater be needed if signals weaken beyond 100 m? (d) Which device in each block connects its computers? (e) What type of network is this?
19.
For http://games.example.com/about.html: (a) Name the protocol and say what it does. (b) What is the top-level domain and what does it tell us? (c) What does a DNS server do with games.example.com? (d) What is the difference between a web browser and a web server?
20.
5 computers are connected (a) in a mesh topology and (b) in a star topology. Find the number of links in each, and give one advantage and one disadvantage of each topology.
AmbifulWorksheets
Practice that never repeats
CBSE · Class 12 · Computer Science

Answer key

Computer Networks · AW-12CS-NET-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.

QAnswerWorking
1(d) ARPANET—
2(a) regenerates a weakened signal so it can travel further—
3(c) LAN—
4(a) 4each node links to the next, and the last back to the first
5(c) 101.203.128.178four numbers, each from 0 to 255, separated by dots
6(a) mail.example.orgthe domain name is the part after :// and before the first /
7(a) each node is connected to two neighbours, forming a closed loop—
8(a) 168 bits make a byte
9Two or more computers linked to share data and resources; it lets users share files and printers and communicate quickly.—
10(a) modem; (b) Wi-Fi carda modem; a Wi-Fi card
11LANLAN: a room, building or campus, up to about 1 km
12(a) 153; (b) 1818 × 17 ÷ 2; one cable per computer
13(a) https; (b) maps.example.com; (c) /docs/report.pdfprotocol://domain/path
14No337 is more than 255
15(a) government; (b) commercialthe top-level domain is the last part of a domain name
16(a) mesh; (b) treemesh; tree
17ARPANET (1969) linked a few research and university computers. In the 1980s NSFNET connected universities with a faster backbone for academic use. Many networks joined them using the TCP/IP protocols, and they grew into the Internet, opened to the public and to business in the 1990s, with the World Wide Web on top.—
18(a) Junior, as it has the most computers (49), so most traffic stays inside it; (b) a star (or tree) topology with Junior at the centre, a cable from it to each other block; (c) on every cable longer than 100 m: Junior–Sports (107 m); (d) a switch; (e) a LAN.the server goes where most computers are; repeaters on long cables
19(a) HTTP: transfers web pages from server to browser; (b) .com: a commercial site; (c) it looks up the IP address of games.example.com so the browser can reach the server; (d) a browser (client) requests and shows web pages; a web server stores them and sends them when asked.URL = protocol://domain/path
20(a) 10 links: very reliable, as a broken link has other paths, but costly to cable; (b) 5 links: easy to add a node and to find faults, but if the central switch fails the whole network stops.5 × 4 ÷ 2 and 5