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Physics · 2022 · 3 marks
Semiconductor Electronics: Materials, Devices and Simple CircuitsSemiconductor Diode3 marksUnderstandshort answer
CBSE 2022 · Region 1 · Set 1 · Q10
State the working principle of an LED. Write any two important advantages and two disadvantages of LED.
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
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CBSE Class 12 Physics past-paper question from the 2022 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.