Question

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20. When a small amount of trivalent impurity is added to an intrinsic semi-conductor, it is called
(A) n-type semi-conductor
(B) p-type semi-conductor
(C) both (a) and (b)
(D) none of above
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Answer 1

Answer:

When the trivalent impurity is added to an intrinsic or pure semiconductor (silicon or germanium), then it is said to be a p-type semiconductor. Trivalent impurities such as Boron (B), Gallium (Ga), Indium(In), Aluminium(Al) etc are called acceptor impurity.