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The diagram Fig.12 shown a piece of pure...

The diagram Fig.12 shown a piece of pure semiconductor S in series with a variable resistor R, and a source of constant voltage V. Would you increase or decrease the value of R to keep the reading of ammeter constant, when semi-conductor S is heated? Give reason.

Text Solution

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(a) When a semiconductor is heated, its resistance decrease i.e., current increases therefore ,
to keep the current constant the value of resistance is to be increased.
(b) When light of energy `hv (hv gt E_(g)` in incident on diode additional e - h phir is formed hear
depletion layer of the diode. e - h pairs are separated before combining by electric field.
E makes electrons to diffuse through junction to reach n-region .

Total reverse current in a photo -diode increases with the increase in intensity of the
incident light.
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