Question Bank — Computer Networks

NCERT Class 12 Computer Science · Chapter 10 · CBSE Board Pattern

Class 12 Computer Science Chapter 10 Question Bank CBSE Board Pattern

Section A — MCQs (10 questions, 1 mark each)

1. Which of the following is the largest example of a WAN?
(a) A network within a single building
(b) Cable TV network in a city
(c) The Internet
(d) Bluetooth connection between two phones

2. A device that converts digital signals to analog signals and vice versa is called:
(a) Switch
(b) Router
(c) Modem
(d) Repeater

3. In which topology is each node connected to exactly two other nodes forming a closed loop?
(a) Star
(b) Bus
(c) Ring
(d) Mesh

4. Assertion (A): A switch sends data packets only to the intended recipient device in a LAN.
Reason (R): A switch maintains a table of MAC addresses and forwards packets selectively.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

5. Which network device regenerates weakened signals on a cable?
(a) Hub
(b) Repeater
(c) Gateway
(d) NIC

6. Assertion (A): IP address of a node can change when it moves from one network to another.
Reason (R): Unlike MAC address, IP address is a logical address assigned by the network.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

7. Which topology requires the highest number of cables for connecting n nodes?
(a) Bus
(b) Star
(c) Ring
(d) Mesh

8. The protocol used to retrieve linked web pages across the web is:
(a) HTML
(b) URL
(c) HTTP
(d) DNS

9. A network covering a city or a town is an example of:
(a) PAN
(b) LAN
(c) MAN
(d) WAN

10. Domain name resolution is performed by:
(a) Gateway
(b) DNS server
(c) Repeater
(d) Ethernet card

Section B — Very Short Answer (6 questions, 2 marks each)

1. Define the term ‘node’ in the context of computer networks.
2. Differentiate between LAN and MAN on the basis of geographical coverage.
3. What is the difference between a hub and a switch?
4. What is a MAC address? State one characteristic of a MAC address.
5. Define the term topology. Name any two network topologies.
6. What is the role of a gateway in a network?

Section C — Short Answer (5 questions, 3 marks each)

1. Explain the function of a modem with the help of a labelled diagram showing modulation and demodulation.
2. Compare star topology and bus topology on the basis of: (i) central device (ii) effect of node failure (iii) security.
3. What is the difference between IPv4 and IPv6 addressing? Give one example of each.
4. Describe the working of a router in a network. How is it different from a switch?
5. Explain how data is transmitted in a ring topology. What happens if one node fails?

Section D — Long Answer (3 questions, 5 marks each)

1. Explain any four network topologies (Mesh, Ring, Bus, Star) with a neat diagram for each. Also state one advantage and one disadvantage of each.
2. What is DNS? Explain the complete process of domain name resolution with the help of a diagram showing the interaction between a browser, DNS server and web server.
3. Draw a trace table showing how a packet travels from a computer in a LAN to a server on another network using the following devices in order: NIC → Switch → Router → Gateway. Briefly explain the role of each device in the path.

Section E — Case/Source-Based (2 questions, 4 marks each)

Case 1: A school plans to set up a network connecting the computer lab (20 computers), library and administrative office located in different buildings within the campus. They also want to provide internet access to all computers.

(i) Which type of network will be most suitable for connecting devices within the campus? Justify.
(ii) Which device will be required at the edge of the school network to connect to the Internet?
(iii) Suggest a suitable topology for connecting the computers in the lab. Give one reason.
(iv) Name the device that can be used to uniquely identify each computer on the network using a permanent address.

Case 2: A student enters the URL https://www.ncert.nic.in in a web browser to access study material.

(i) What is the role of HTTP/HTTPS in this process?
(ii) Which server is first contacted by the browser to obtain the IP address?
(iii) What is the difference between the domain name and the IP address of the website?
(iv) Name the protocol/technology used to design the web pages that the student will see.

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Section A

  1. (c)
  2. (c)
  3. (c)
  4. (a)
  5. (b)
  6. (a)
  7. (d)
  8. (c)
  9. (c)
  10. (b)

Section B

  1. A node is any device that can receive, create, store or send data on a network (modem, computer, printer, switch, etc.).
  2. LAN covers a small area (room/building/campus) up to 1 km; MAN covers a city/town up to 30–40 km.
  3. Hub broadcasts data to all ports; switch forwards data only to the destination port using MAC table.
  4. MAC address is the 48-bit permanent hardware address engraved on the NIC by the manufacturer.
  5. Topology is the physical or logical arrangement of nodes in a network. Examples: Star, Bus.
  6. Gateway acts as the entry/exit point between an organisation’s network and external networks (Internet).

Section C

  1. Modem converts digital data to analog (modulation) at sender and analog to digital (demodulation) at receiver.
  2. Star: central switch/hub, single node failure does not affect others, more secure. Bus: shared backbone, node failure may affect network, less secure.
  3. IPv4: 32-bit, e.g., 192.168.0.1; IPv6: 128-bit, e.g., 2001:CDBA:0000:0000:0000:0000:3257:9652.
  4. Router analyses packets, decides best path and can connect different network types; switch works only within a LAN using MAC addresses.
  5. Data travels in one direction around the ring; failure of one node breaks the ring and stops transmission.

Section D

  1. (Mesh: every node connected to every other – reliable but costly; Ring: nodes in a loop – unidirectional; Bus: shared cable – cheap but single point of failure; Star: central device – easy to manage but central failure affects all.)
  2. DNS server converts domain name to IP address. Browser sends request → DNS returns IP → HTTP fetches page from web server.
  3. Trace table example:
    - NIC: attaches packet with source MAC
    - Switch: forwards using destination MAC within LAN
    - Router: routes packet to another network using IP
    - Gateway: performs protocol conversion and forwards to Internet

Section E

Case 1

(i) LAN – limited geographical area inside campus.
(ii) Gateway/Router (connected to ISP).
(iii) Star – easy management and fault isolation.
(iv) NIC (MAC address).

Case 2

(i) HTTP/HTTPS is the protocol to request and transfer web pages.
(ii) DNS server.
(iii) Domain name is human-readable (ncert.nic.in); IP address is numeric (164.100.60.233).
(iv) HTML.

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All questions are answerable from the NCERT chapter text. Reviewed by GFIS faculty.