Computer: Chapter 1 (Class VIII)
Computer
Chapter - 1
Computer Network
D. Define the following:
1. Network: A computer network is a collection of computers and devices connected by communication channels.
2. Protocol: A protocol is a set of rules that outlines the characteristics of how two devices communicate over the network.
3. Router: A router is a device that connects multiple computers together and transmits data to its correct destination on a network.
4. FTP: FTP stands for File Transfer Protocol. This is a set of rules that allows file uploading and downloading on the internet.
5. SMTP: SMTP stands for Simple Mail Transfer Protocol. This is an email protocol for sending emails across the internet.
E. Differentiate between the following:
Answer 1.
POP3
(i) The user can view and access the emails after downloading them to their device.
(ii) The emails can only be accessed from the device on which they were downloaded.
IMAP
(i) The user doesn’t have to download the emails to their device. They can view and access the emails on the mail servers.
(ii) The emails can be accessed from any device.
Answer 2.
Hub
Hub sends data to every computer connected to it.
Switch
Switch sends the data only to the computer that requests for it.
Answer 3.
LAN
(i) It stands for Local Area Network.
(ii) It is a network that connects the devices in a limited area such as school, office etc.
WAN
(i) It stands for Wide Area Network.
(ii) It is a network that connects the devices in a large area like a country or all over the world.
Answer 4.
Star Topology
In this topology a hub is placed at the centre to which all the other nodes are connected.
Ring Topology
In this topology, the nodes are connected in a circular chain in which the last node is connected to the first one.
Answer 5.
Physical Transmission
Physical transmission media use wire or cable to send communication signals.
Wireless Transmission
Wireless transmission media send communication signals through the air.
Answer 6.
Twisted Pair cable
i. Twisted pair cables consist of one or more twisted-pair wires bundled together.
ii. They are used in landline phones and LANs.
Coaxial cable:
i. Coaxial cables consist of a single copper wire surrounded by three layers.
ii. They are used in Cable TV networks.
F. Answer in 1-2 sentences:
Ans 1. Communication is a process in which two or more people share their information and resources among themselves.
Ans 2. A computer network is a collection of computers and devices connected by communication channels.
Ans 3. Network Interface Card is used to provide network access to a computer or other device, such as a printer.
Ans 4. The network architecture refers to how computers are organised and how tasks are allocated among the computers. It categorised into two major types:
(i) Peer-to-Peer network
(ii) Client/Server Network
Ans 5. Communication channel is a medium through which the data or information can travel.
Ans 6. A communication satellite is a space station that receives microwave signals from an earth based station, strengthens the signals, and broadcasts the signal back over a wide area to any number of earth based stations.
G. Answer Briefly:
Answer 1. The basic requirements for computer communication are:
(i) sender
(ii) communication channel
(iii) receiver
(iv) protocol
Answer 2. The different types of networks are:
Different types of networks are: LAN (Local Area Network), MAN (Metropolitan Area Network), WAN (Wide Area Network) and PAN (Personal Area Network).
MAN: It is a network that connects the Local Area Networks in a metropolitan area such as a city or a town.
PAN: It is a network that connects personal devices like laptop, smartphones, digital cameras, printers etc. in an individual’s workspace.
Answer 3. Different types of Network architecture are:
(i) Peer-to-Peer Network: A network of two or more computers that uses the same type of programs to communicate and share data.
(ii) Client/Server Network: A network which has a client and a server is called client/server network.
Answer 4. Network topology: It refers to the layout structure of connected computers and devices on a network.
Bus topology: In bus topology all the computers and devices are connected to single cable called the bus.
Answer 5. The different types of wireless transmission media are:
(i) Infrared
(ii) Broadcast Radio
(iii) Cellular Radio
(iv) Wi-Fi
(v) Microwave
(vi) Communication Satellite