The gap between the valence and conduction bands of a certain semiconductor is 0.85 eV. When this semiconductor is used to form a light emitting diode, the wavelength of the light emitted.
Answer & explanation
Correct answer: option 2
$\lambda_{max} = \frac{hc}{E} = \frac{12400 A^o}{0.85} = 1.5 \mu m$
$\lambda \text{ is less than }1.5 \mu m$.