This page contains the NCERT Computer Science class 12 chapter 10 Computer Networks. You can find the solutions for the chapter 10 of NCERT class 12 Computer Science Exercise. So is the case if you are looking for NCERT class 12 Computer Science related topic Computer Networks questions and answers for the Exercise
Exercise
Question 1
1. Expand the following:
a)
ARPANET
b)
MAC
c)
ISP
d)
URI
Answer 1
a)
ARPANET: Advanced Research Projects Agency Network
b)
MAC: Media Access Control
c)
ISP: Internet Service Provider
d)
URI: Uniform Resource Identifier
Question 2
2. What do you understand by the term network?
Answer 2
A network is a group of two or more devices that are interconnected to share information and resources. A computer network is an interconnection among two or more computers/computing devices to share data and resources.
Question 3
3. Mention any two main advantages of using a network of computing devices.
Answer 3
1.
Information sharing / communication: Interconnectivity allows us to exchange information simultaneously with many parties through email, websites, audio/video calls, etc.
2.
Resource sharing: A network allows sharing of resources. For example, one printer can be used by multiple computers, and networked storage can also be accessed by multiple computers.
Question 4
4. Differentiate between LAN and WAN.
Answer 4
Basis
LAN (Local Area Network)
WAN (Wide Area Network)
Full form
Local Area Network
Wide Area Network
Meaning / Coverage area
Connects devices placed at a limited distance such as a room, floor, office, lab, school/college/university campus.
Connects computers and even other LANs/MANs spread across different geographical locations, like different cities/states/countries/continents.
Connectivity media
Uses wires/Ethernet cables/fibre optics/Wi-Fi in a local area.
Can be formed by connecting LANs through wired/wireless media over long distances.
Speed / Range (as given)
High speed; can be extended up to 1 km; typically 10 Mbps to 1000 Mbps.
Very large coverage; used to connect branches across the world (no specific Mbps value stated here).
Example
A network inside a school lab/office building/campus.
Internet is the largest WAN connecting billions of devices and many LANs worldwide.
Question 5
5. Write down the names of few commonly used networking devices.
Answer 5
•
Modem
•
Hub
•
Switch
•
Repeater
•
Router
•
Gateway
•
NIC (Network Interface Card)
Question 6
6. Two universities in different States want to transfer information. Which type of network they need to use for this?
Answer 6
They should use a WAN (Wide Area Network) because WAN connects computers and networks spread across different geographical locations (different states/cities/countries).
Question 7
7. Define the term topology. What are the popular network topologies?
Answer 7
Topology is the arrangement of computers and peripherals in a network (how devices are connected).
Popular network topologies:
•
Mesh Topology: Each communicating device is connected with every other device in the network.
•
Ring Topology: Each node is connected to two other devices, one on either side, forming a ring; the link is unidirectional (data moves in one direction only).
•
Bus Topology: Each device connects to a single transmission medium called bus; data sent by a node travels along the bus, and can be received by nodes connected to it.
•
Star Topology: Each device is connected to a central node (networking device like a hub or switch).
•
Tree / Hybrid Topology: A hierarchical topology with multiple branches; each branch can have one or more basic topologies like star, ring, bus (often used when multiple LANs are connected).
Question 8
8. How is tree topology different from bus topology?
Answer 8
Basis
Bus Topology
Tree (Hybrid) Topology
Basic idea / structure
All devices are connected to a single transmission medium called bus.
It is a hierarchical topology with multiple branches.
Connection style
Uses one main cable (backbone) shared by all nodes.
Each branch can use one or more basic topologies like star, ring, or bus.
Typical use (as per book)
Suitable for a simple network where devices share the same bus line (bus acts as the common medium).
Used mainly when multiple LANs are connected (because it can combine more than one topology).
Question 9
9. Identify the type of topology from the following:
a)
Each node is connected with the help of a single cable.
b)
Each node is connected with central switching through independent cables.
Answer 9
(a)
Bus topology (single cable/backbone shared by nodes).
(b)
Star topology (each node connected to a central device like hub/switch through separate cables).
Question 10
10. What do you mean by a modem? Why is it used?
Answer 10
A modem stands for MOdulator DEModulator. It is used for conversion between analog signals and digital bits. It converts digital data to analog signals for transmission and converts received analog signals back to digital data so the computer can understand it.
Question 11
11. Explain the following devices:
a)
Switch
b)
Repeater
c)
Router
d)
Gateway
e)
NIC
Answer 11
(a)
Switch: A networking device that connects multiple devices and forwards data to the selected destination node (not to everyone).
(b)
Repeater: An analog device that regenerates weak signals on cables so the signal can travel a longer distance.
(c)
Router: A device that can receive, analyse and transmit data to other networks (connects networks).
(d)
Gateway: Works as the entry and exit point of a network; provides routing paths and data passes through it.
(e)
NIC (Network Interface Card): A network adapter card used to set up a wired network; installed in a computer to connect it to the network and has a unique MAC address for identification.
Question 12
12. Draw a network layout of star topology and bus topology connecting five computers.
Answer 12
(A) Star Topology (5 computers)
All computers connect to a central device (hub/switch).
PC1 PC2
\ /
\ /
[SWITCH]
/ | \
/ | \
PC3 PC4 PC5Star Topology (5 Computers)
(B) Bus Topology (5 computers)
All computers share a single backbone cable (bus).
PC1 PC2 PC3 PC4 PC5
| | | | |
================================ (BUS)Bus Topology (5 Computers)
Question 13
13. What is the significance of MAC address?
Answer 13
A MAC address (Media Access Control address) is the physical/hardware address of a computer/device. It is a unique and permanent value assigned to the NIC (Network Interface Card).
Significance:
It is used for unique identification of a computer/device on a network (i.e., it helps to identify a node uniquely at the physical level).
Question 14
14. How is IP address different from MAC address? Discuss briefly.
Answer 14
Basis
IP Address
MAC Address
Meaning
Internet Protocol (IP) address is used to identify a node on a network.
MAC (Media Access Control) address is the physical/hardware address of a computer/device.
Nature
It is generally not permanent; it can change when a computer moves from one network to another.
It is unique and permanent (assigned to the NIC).
Also called
Logical / network address (used for identifying the node in the network).
Physical / hardware address (used for physical identification of the device).
Question 15
15. What is DNS? What is a DNS server?
Answer 15
DNS (Domain Name System): DNS is a system used for domain name resolution, i.e., it converts the domain name of a web server into its corresponding IP address.
DNS Server: A DNS server is a server that performs domain name resolution by maintaining a database of domain names and their corresponding IP addresses.
Question 16
16. Sahil, a class X student, has just started understanding the basics of Internet and web technologies. He is a bit confused in between the terms “World Wide Web” and “Internet”. Help him in understanding both the terms with the help of suitable examples of each.
Answer 16
Internet:
The Internet is the global network of computing devices (computers, servers, mobiles, routers, etc.) connected together. It is like the network/backbone that provides connectivity.
Example (Internet):
•
Sending an email / doing an audio-video call / connecting your computer to your ISP network (all need Internet connectivity).
World Wide Web (WWW) / Web:
The World Wide Web (WWW) (or web) is an ocean of information, stored as trillions of interlinked web pages and web resources. These web pages/resources are accessed through the Internet. The Internet is the global network, while the web is the interlinking of webpages on these computers accessible over the Internet.
Example (WWW):
•
Opening a website in a browser (like visiting a page using its URL) and reading information from web pages.
✅ In short:
•
Internet = the global network (connection system).
•
WWW/Web = interlinked web pages/resources that we access using the Internet.