Q. With reference to Light-Emitting Diodes, consider the following statements:
1. These are semiconductor devices that emits light when an electric current is passed through it.
2. In default, all LEDs emit white light.
Which of the statements given above is/are correct?
Answer: A
Notes:
Statement 1 is correct: A light-emitting diode (LED) is a semiconductor device that emits light when an electric current is passed through it.
Statement 2 is incorrect: Conventional LED materials cannot emit white light and specialised techniques, such as coating blue LED with yellow phosphor and combining blue, green and red LEDs, have been used to produce white light.
Source: IIT-Madras researchers design white light emitters for LED applications
