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14. Semicondutor electronics — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics14. Semicondutor electronics1 Mark
MCQ
Consider a situation in which reverse biased current of a particular $P-N$ junction increases when it is exposed to a light of wavelength $\le 621\, {nm}$. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly. (In ${eV}$)
  • A
    $1$
  • ✓
    $4$
  • C
    $2$
  • D
    $0.5$
✓

Answer

Correct option: B.
$4$
b
Band gap $=\frac{h c}{\lambda_{0}}$

Where $\lambda_{0}=$ threshold wavelength

Band gap $=\frac{1242\, {ev}-\,{nm}}{621\, {nm}}=2\, {ev}$

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