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MHT CET 2026 (12 May, Shift 2) · Intrinsic & Extrinsic Semiconductors

Intrinsic & Extrinsic Semiconductors question from MHT CET 2026 (12 May, Shift 2)

Q9MHT CET 2026 · 12 MAY · SHIFT 2Easy

Intrinsic & Extrinsic Semiconductors

Pure silicon crystal at 300300K has equal electron and hole concentration 2×10162 \times 10^{16} per m3{}^{3}. Doping by indium increases hole concentration to 4×10224 \times 10^{22} per m3{}^{3}. Electron concentration in doped silicon is

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Answer: (b)

  1. Mass action law: nenh=ni2n_e n_h = n_i^2
  2. ne=(2×1016)24×1022=4×10324×1022n_e = \dfrac{(2\times10^{16})^2}{4\times10^{22}} = \dfrac{4\times10^{32}}{4\times10^{22}}
  3. ne=1010 m−3n_e = 10^{10}\ \text{m}^{-3}
  4. So the answer is (b) 1010/m310^{10}/\text{m}^3.
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