The energy band gap of semiconducting material to produce violet (wavelength = 4000$\mathop A\limits^o$ ) LED is ______________ $\mathrm{eV}$. (Round off to the nearest integer).
Answer (integer)
3
Solution
<p>Energy corresponding to wavelength 4000 $\mathop A\limits^o$</p>
<p>$E = {{hc} \over \pi }$</p>
<p>$$ = {{6.6 \times {{10}^{ - 34}} \times 3 \times {{10}^8}} \over {4000 \times {{10}^{ - 10}} \times 1.6 \times {{10}^{ - 19}}}}$$ eV</p>
<p>$= {{12400} \over {4000}}$</p>
<p>$=3.1$ eV</p>
<p>$\approx$ 3 eV</p>
About this question
Subject: Physics · Chapter: Electronic Devices · Topic: Semiconductors
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