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JEE Mains · Physics · STD 12 - Semicondutor electronics
  • JEE Mains 2021
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  • MCQ

\(LED\) is constructed from \(Ga-As-P\) semiconducting material. The energy gap of this \(LED\) is \(1.9\, eV\). Calculate the wavelength of light emitted and its colour. \(\left[ h =6.63 \times 10^{-34} \;Js \right.\) and \(\left. c =3 \times 10^{8}\; ms ^{-1}\right]\)

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Answer & Solution

Correct Answer

(D) \(654\, nm\) and red colour

Step-by-step Solution

Detailed explanation

\(\lambda=\frac{ hc }{ E }=\frac{6.6 \times 10^{-34} \times 3 \times 10^{8}}{1.9 \times 1.6 \times 10^{-19}}=6.54 \times 10^{-7}\)

\(=654 nm\)

Red color

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