State any four applications of LEDs.

Explanation

Applications of LEDs.
(1) An LED is commonly used as an On/Off indicator lamp on electrical equipments.
(2) LEDs are used in self-luminous seven-segment alpha-numeric displays of calculators and digital clocks and meters, signages, etc.
(3) Because of their law power consumption. LEDs are now commonly used for household lighting and in traffic signals, handheld torches and various indicator lamps in light motor vehicles and two-wheelers.
(4) Under certain conditions, the essentially monochromatic light emitted by an LED is also coherent. Such diode lasers are used in optical fibre communications, CD players, CDROM drives, laser printers, bar code scanners, laser pointers, etc.