Internet is popularly known as network of networks.
Internet helps any computer system/mobile to connect with any other computer system globally using TCP/IP protocol. TCP/IP protocol is also known as Internet protocol.
Internet identifies each system in the network through a unique address known as IP address. Each computer system has a unique IP to distinguish from other computer on the network just like voter id of human beings.
When you type 'Tutorials In Hand' on Google then your search query is sent via internet to a special computer known as Domain Name Server (DNS).
DNS will resolve the query string 'Tutorials In Hand' to unique IP address that is assigned to it.
This IP address takes you to the computer on which the website is hosted. This is how you get to see our website or any other website that you search.
The amount of data that is transmitted in a fixed amount of time through internet (network connection) is known as bandwidth.
The bandwith is measured in bits per sec (bps) or kilobits per sec (kbps) or megabits per sec (mbps)
Advantages of Internet
And many more
Disadvantages of Internet
Prone to network disruption or outage hampering services temporarily.