CBSE 2022 · Region 1 · Set 1 · Q10 · 3 marks
State the working principle of an LED. Write any two important advantages and two disadvantages of LED.
Marking-scheme solution
When the diode is forward biased, electrons are sent from n region to p region and holes are sent from p region to n region. At the junction the concentration of minority carriers increases. Thus at the junction, the excess minority carriers recombine with majority carriers and energy is released in the form of photons.
Advantages :
(i) Low operational voltage
(ii) Less power consumption
(iii) Fast action
(iv) Long life and ruggedness
Disadvantages :(i) High cost
(ii) Can get damaged due to overheating
(iii) Excess of voltage or current can damage LED
Semiconductor Electronics: Materials, Devices and Simple CircuitsSemiconductor DiodeUnderstandshort_answereasy
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CBSE Class 12 Physics past-paper question from the 2022board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.