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Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronic: Material, Devices And Simple Circuits1 Mark
Question
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from thecodes(a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion: The ratio of free electrons to holes in intrinsic semiconductor is greater than one.
Reason: The electrons are lighter particles and holes are heavy particles.
✓

Answer

  1. Both A and R are true but R is not the correct explanation of A.
Explanation:

In intrinsic semiconductor $\frac{\text{n}_\text{e}}{\text{n}_\text{h}} = \text{I}$ and holes are not particles but vacancies created due to breakage of covalent bond.

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