Computer Hardware Devices

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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Reel-to-reel tape drives were historically used for bulk data storage and backups in large-scale systems like mainframes.

In a hard disk drive, there is one read/write head for each recording surface of the disk stack.

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.

In master-slave architecture, a device that operates under the control of another (the master) is called a slave device.

A teleprocessing terminal acts as an input/output device that allows users to enter data into a remote computer system.

A writing tablet, or digitizer, is an input device that allows users to hand-draw images or write text, which is then converted into digital data. Other options like mice or touch panels do not primarily serve the function of converting handwritten impressions into specific positional coordinates.

An off-line device is one that is not currently connected to or under the direct control of the CPU. This is the opposite of an on-line device, which is actively communicating with the processor.