Choose valid set of output devices:

Question

Accepted Answer

The correct option is (3):
Plotter, VDU (Visual Display Unit, or monitor), and Headphone are all classified as pure output devices, meaning their primary function is to communicate processed data from the computer to the user in a usable format. A Plotter is a specialized printer used to produce high-quality, large-format graphic output like engineering drawings and architectural blueprints. The VDU, which is essentially the computer monitor, is the main soft-copy output device, displaying visual information such as text, images, and video. Headphones are personal audio devices that take electrical signals from the computer's sound card and convert them into audible sound waves for the user to hear, making them clear output components. Therefore, this set is the only one in which all components function solely as output devices.

The incorrect option is (1):
This option is invalid because it contains two distinct input devices. While the Printer is correctly identified as an output device (producing hard-copy output), the MICR (Magnetic Ink Character Recognition) Reader is an input device specifically designed to read bank routing and account numbers printed with magnetic ink on checks. Similarly, a Bar Code Reader is an input device used to optically scan and decode the data stored in printed barcodes. Because they capture data and send it *into* the system for processing, MICR and Bar Code Readers invalidate this set.

The incorrect option is (2):
This set is incorrect because one of its components is a primary input device. The Speaker and VDU are correctly categorized as output devices for audio and visual information, respectively. However, the OMR (Optical Mark Recognition) Reader is a dedicated input device. Its function is to sense and interpret the presence or absence of a mark in a specific position on a printed form, most famously used for automatically grading multiple-choice exams, making it an information-capturing component, not an output one.

The incorrect option is (4):
Like the other invalid options, this set includes components that fall under the input category. The Headphone is an audio output device, converting digital audio signals into sound waves. However, OCR (Optical Character Recognition) is a technology that uses an input device, typically a scanner, to capture printed or handwritten text and convert it into machine-encoded text. Additionally, a Joystick is a classic input device used to control movement or actions, primarily in computer gaming, by translating physical motion into digital signals for the computer.