Describe briefly lhow light emitting diode is fabricated and expalin its working write three important advantages of LED over conventional incandescent lamps

Give any one advantage of LEDs over conventional incandescent low power lamps

What is light emitting diode (LED) ? Mention two important advantages of LEDs over con-ventional lamps.

Mention three molecular diagnostic techniques which help to detect pathogens from suspected patients. Write the advantage of these techniques over conventional methods.

Draw a schematic ray diagram of reflecting telescope showing how rays coming from a distant object are received at the eye - piece . Write its two important advantage over a refracting telescope.

(a) Describe briefly with the help of a diagram the role of the two important processes involved in the formatiojn of a p-n junction (b) Name the device which is used as a voltage regulator draw the necessary cirucit diagram and explain its working