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Given reasons for the following : (i) ...

Given reasons for the following :
(i) High reverse voltage do not appear across a LED.
(ii) Sunlight is not always required for the working of a solar cell.
(iii) The electric field, of the junction of a Zener diode, is very high even for a small reverse bias voltage of about 5 V.

Text Solution

Verified by Experts

(i) Because of its heavy doping as reverse voltage is applied minority carriers increases near junction and current starts flowing.
(ii) Because energy produced by solar cell can be stored in batteries for later use, when sunlight is not available.
(iii) As the depletion width si very small `(lt10^(_7))` even a small voltage say 5V can set up a very high electric field as `E=(V)/(d)`.
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