Danny is buying a new computer that has an LED display. Which of the following…

Concept

A light-emitting diode (LED) produces light when current passes through its semiconductor junction. In a display, many such light-producing elements are arranged as a thin, flat panel.

Colour displays form pixels by controlling red, green and blue light components. LED-based display systems are valued for compact construction and comparatively efficient operation, and they are used in devices of many sizes.

Application

• The flat-panel statement is true: LED display assemblies have a thin, flat-panel form.

• The red-green-blue diode statement is true in the exam's intended description: varying these three colour components produces the displayed colours.

• The statement describing the display as energy-inefficient and strongly heat-producing is false; energy efficiency and lower heat generation are standard advantages of LED technology compared with older display or lighting technologies.

• The mobile-device statement is true: LED-family display technologies are used in smartphones, tablets and other compact devices.

• The statement that every LED display is front-lit is false; LED elements may emit the image light directly, or LEDs may provide backlighting in an LCD system, so front-lighting is not universal.

Cross-check and contrast

• The true statements describe the panel form, RGB colour formation and use in mobile devices.

• The two excluded statements use claims that conflict with characteristic advantages or construction: poor efficiency with substantial heat, and universal front-lighting.

Therefore, the true set is A, B and D only.