Bluetooth, Wi-Fi are used to connect to internet without using any connecting cables / devices.
(i) Bluetooth
Mouse, Keyboard can be connected to the computer using the Bluetooth. Using Bluetooth the data can be shared with nearby devices.
(ii) Wi-Fi
Net connectivity can be obtained using the Wi-Fi without any connecting cables. Any data from anywhere can be shared using Wi-Fi.

Video Graphics Array (VGA), High Definition Multimedia Interface (HDMI),
Universal Serial Bus (USB), Data cable, Power Cord, Mic cable, Ethernet cable.
(i) VGA Cable:
It is used to connect the computer monitor with the Cl'U.
(ii) USB cable /cord:
Devices like Printer, Pendrive, Scanner, Mouse, Keyboard, web camera, and
Mobile phone devices are connected with the computer using USB cord or cable.
(iii) HDMI Cable:
HDMI cable transmits high quality and high bandwidth streams of audio and video. It connects monitor, projector with the computer.
(iv) Data Cable:
Data cable transmits data and it is used to connect tablet, mobile phones to the CPU for data transfer.
(v) Audio jack:
The audio jack is used to connect the speaker to the computer.
(vi) Power cord:
Power cord temporarily connects an appliance to the main electricity supply.
(vii) Mic cable:
To connect the Mic to the CPU, Mic wire/cord is used.

The computers can be classified as follows based on their design, shape, speed, efficiency, working of the memory unit and their applications.
(i) Mainframe Computer
(ii) Mini Computer
(iii) Micro or personal computer
(iv) Super computer

Keyboard and mouse are the important input units. Keyboard plays an important role in a computer as an input device. Numbers and alphabet plays a role of data in computer. Keyboard helps to enter data. Keyboard has two types of keys, namely number keys and alphabet keys. The keys with numbers are called number keys and the keys with letters are called alphabet keys

Three parts of the computer are:
(i) Input Unit
(ii) Central Processing Unit (CPU)
(iii) Output Unit.