Physics - Semiconductors Question with Solution | TestHub

For same value of current higher value of voltage is required for higher frequency hence,

${\mathrm{V}}_{\mathrm{T}\mathrm{h}}\propto \mathrm{\Delta }{\mathrm{E}}_{\mathrm{g}}\propto \frac{1}{\mathrm{\lambda }}$

LED works in forward Bias. This graph is correct.