NCERT Solutions Class 12, Computer Science, Chapter- 10, Computer Networks
Exercise
1. Expand the following:
a) ARPANET
b) MAC
c) ISP
d) URI
Solution:
a) ARPANET: Advanced Research Project Agency Network
b) MAC: Media Access Control
c) ISP: Internet Service Provider
d) URL: Uniform Resource Locator
2. What do you understand by the term network?
Solution:
A group of two or more similar things or people interconnected with each other is called a network. For example Social networks, Mobile networks, Networks of computers, Airlines, railways, banks, hospitals networks, etc.
3. Mention any two main advantages of using a network of computing devices.
Solution:
The advantages of using a Network of Computing devices are:
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Resource Sharing: Through a network, data, software, and hardware resource can be shared irrespective of the physical location of the resources and the user.
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Reliability: Files can be stored on any computer, so it makes a network more reliable.
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Reduced Cost: Resources can be shared, which greatly reduces costs.
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Fast Communication: It helps in exchanging information very fast.
4. Differentiate between LAN and WAN.
Solution:
| LAN |
WAN |
| LAN is spread over a small area. |
WAN is spread over a very large area. |
| It usually costs less to set it up. |
It costs higher to set it up. |
| It is usually a single network. |
It is usually a network of many networks. |
5. Write down the names of few commonly used networking devices.
Solution:
Some networking devices are Routers, Modems, Repeaters, Ethernet cables, Gateways, wifi, etc.
6. Two universities in different States want to transfer information. Which type of network they need to use for this?
Solution:
WAN
7. Define the term topology. What are the popular network topologies?
Solution:
The arrangement of computers and other peripherals in a network is called its topology.
Common network topologies are Mesh, Ring, Bus, Star, and Tree.
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Mesh Topology: In this topology, each communicating device is connected with every other device in the network. Such a network can handle large amounts of traffic since multiple nodes can transmit data simultaneously.
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Ring Topology: In a ring topology, each node is connected to two other devices, one each on either side, thus forming a ring. The link in a ring topology is unidirectional. Thus, data can be transmitted in one direction only (clockwise or counterclockwise).
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Bus Topology: In a bus topology, each communicating device connects to a transmission medium, known as a bus. Data sent from a node are passed on to the bus and hence are transmitted to the length of the bus in both directions.
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Star Topology: In star topology, each communicating device is connected to a central node, which is a networking device like a hub or a switch.
8. How is tree topology different from bus topology?
Solution:
Bus topology is connected with a single cable without any interconnection but tree topology is in the form of nodes of a tree structure. The bus topology is a network topology in which each node is linked to a single main cable that serves as the network's backbone. The nodes in the tree topology are arranged in the shape of a tree. Each included node in a bus topology is linked to a single cable known as the backbone.
9. Identify the type of topology from the following:
a) Each node is connected with the help of a single cable.
Solution:
BUS TOPOLOGY
b) Each node is connected with central switching through independent cables.
Solution:
STAR TOPOLOGY
10. What do you mean by a modem? Why is it used?
Solution:
Modem stands for ‘Modulator DeModulator’. It refers to a device used for conversion between analog signals and digital signals.
The modem converts digital signals to analog signal (audio frequency) tones which are in the frequency range that the telephone lines can transmit and also it can convert transmitted tones back to digital information.
