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TNPSC Group-I 2017 · Question 2 of 71

The valence electron of the impurity atom that is to be added to germanium crystal so as to make it a n-type semiconductor is

Science - Physics

  1. A6
  2. B5Correct
  3. C4
  4. D3

Answer: B. 5

Explanation

A pentavalent (5 valence electrons) impurity like phosphorus or arsenic is added to germanium to make an n-type semiconductor; the fifth electron becomes the free charge carrier.

Source: TNPSC Group-I Prelims 2017 (GS1902) - Official Question Paper (scribd OCR, tick-marked answers)

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