Which of the following is an input device?
Scanner
Understanding Input and Output Devices in Computers
Computer peripherals are devices that connect to a computer system to expand its capabilities. These devices are broadly categorized into input devices and output devices.
An input device is a piece of computer hardware that allows a user to send data, information, or control signals to a computer. It converts external data into a format that the computer can process. Examples include keyboards, mice, microphones, and scanners.
An output device is a piece of computer hardware that receives data from the computer and displays it to the user or another device in a human-readable or machine-readable format. Examples include monitors, printers, speakers, and headphones.
Analyzing the Given Options
Let's examine each option provided to determine whether it is an input device or an output device:
- Printer: A printer takes data from the computer (a document or image) and creates a physical copy on paper. It outputs information. Therefore, a printer is an output device.
- Headphone: Headphones take audio data from the computer and convert it into sound waves that a user can hear. They output audio. Therefore, headphones are an output device.
- Monitor: A monitor takes video data from the computer and displays it visually on a screen. It outputs visual information. Therefore, a monitor is an output device.
- Scanner: A scanner takes a physical document or image and converts it into a digital format (like a file) that the computer can store and process. It inputs data from the physical world into the computer. Therefore, a scanner is an input device.
Based on this analysis, the scanner is the device that fits the definition of an input device among the given options.
Revision Table: Input vs. Output Devices
| Device | Category | Function |
|---|---|---|
| Printer | Output | Produces hard copy (paper) from digital data. |
| Headphone | Output | Produces sound from digital audio data. |
| Monitor | Output | Displays visual information from digital data. |
| Scanner | Input | Converts physical documents/images into digital data. |
Additional Information: Other Peripheral Device Types
Beyond input and output, devices can also be categorized:
- Storage Devices: Devices that store data, either temporarily or permanently. Examples include hard drives, SSDs, USB flash drives, and optical drives (CD/DVD). Some storage devices can act as both input (reading data) and output (writing data) in different operations.
- Communication Devices: Devices that allow computers to exchange data with other computers or networks. Examples include modems, network interface cards (NICs), and routers.
Understanding the function of different peripheral devices is key to understanding how computers interact with the external world and other systems.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A sphere of volume V is made of a material with lower density than water. While on Earth, it floats on water with its volume f1V (f1 < 1) submerged. On the other hand, on a spaceship accelerating with acceleration a < g (g is the acceleration due to gravity on Earth) in outer space, its submerged volume in water is f2V. Then:
A railway wagon (open at the top) of mass M1 is moving with speed v1 along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M2 and speed becomes v2. Taking the rain to be falling vertically and the water stationery inside the wagon, the relation between the two speeds v1 and v2 is :
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
One block of 2⋅0 kg mass is placed on top of another block of 3⋅0 kg mass. The coefficient of static friction between the two blocks is 0⋅2. The bottom block is pulled with a horizontal force F such that both the blocks move together without slipping. Taking acceleration due to gravity as 10 m/s2, the maximum value of the frictional force is :
