Chapter 15, Problem 15C.2ST

Interpretation Introduction

Interpretation:

From the band gap energies given, the colours for the given materials has to be predicted.

Concept Introduction

The electronic absorption frequency is given by the formula

    $\begin{array}{l}\text{ν =}\frac{{\text{E}}_{\text{g}}}{\text{h}}\stackrel{}{\to }\text{(1)}\\ \text{ν =}\frac{\text{c}}{\text{λ}}\stackrel{}{\to }\text{(2)}\\ \text{Substituting (2) in (1)}\\ \frac{\text{c}}{\text{λ}}\text{ = }\frac{{\text{E}}_{\text{g}}}{\text{h}}{\text{, E}}_{\text{g}}\text{=}\frac{\text{hc}}{\text{λ}}\end{array}$

    $\begin{array}{l}\text{ν = absorptionfrequency}\\ \text{h = planck'sconstant}\\ {\text{E}}_{\text{g}}\text{= band-gap energy}\\ \text{λ = wavelength}\\ \text{c = velocity of light}\end{array}$