Question

The Cauchy's formula is

• A. $\mu=A+B \lambda^{2}+C \lambda^{4}$
• B. $h=A+B \lambda^{2}+C \lambda^{2}$
• C. $\mu=A - B \lambda^{2}+C \lambda^{4}$
• D. $\mu=A+B \lambda^{-2}+C \lambda^{-4}$

Answer 1

Answer: (D)

From Cauchy's dispersion formula the refractive index $(\mu)$ and wavelength $(\lambda)$ are related as follows:
$\mu=A+\frac{B}{\lambda^{2}}+\frac{C}{\lambda^{4}}$
$\Rightarrow \mu=A+B \lambda^{-2}+C \lambda^{-4}$