Computer Hardware Devices

A dumb terminal is a device that has no local processing power. It consists essentially of a keyboard for input and a Video Display Unit (VDU) for output.

PDA stands for Personal Digital Assistant, a term used for handheld devices that functioned as personal information managers.

A light pen is an input device that uses a light-sensitive detector to allow a user to point to displayed objects or draw on the screen in a similar way to a touchscreen.

Because there is four pin USB port in the system and the cable end A also have four pin connector.

 IRQ 1 enables keyboard to communicate with the microprocessor. If we assign the same IRQ to two devices, this will result in an IRQ conflict and the system or the device may malfunction.

A camera is a device which is used to view the object on a screen. Periscope is a device used to see the concealed positioned objects, a microscope to look the larger view of very small objects which are not visible with the naked eye. Mirror produces and image only till the time that a particular object is lying in its path.

Structure of a pinhole camera is easy and can be easily constructed at home by using general materials from the surroundings like cardboard trace paper etc. But digital camera, CD or cellophane sheet requires an expertise hand and some mechanical devices so cannot be constructed at home.

Keyboards, mice, and scanners are all devices used to input data into a computer system.

Printers, speakers, and screens (monitors) are all devices used to output data from a computer system.

A PDA (Personal Digital Assistant) is a mobile device, not a data scanning unit like OMR, barcode readers, or OCR systems.

Membrane switch keyboards use a sealed plastic layer, making them resistant to spills, liquids, and grease compared to mechanical keyboards.

The keyboard controller is the internal processor that detects when a key is pressed, identifies the scan code, and sends it to the computer.

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EFT (Electronic Funds Transfer) is a digital process and does not rely on physical media like mark sensing or MICR in the way the question implies.

Option (2) is correct.