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Dispersion and Spectra — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsDispersion and Spectra3 Marks
Question
A certain material has refractive indices $1.56, 1.60$ and $1.68$ for red, yellow and violet light respectively.
  1. Calculate the dispersive power.
  2. Find the angular dispersion produced by a thin prism of angle $6^\circ$ made of this material.
✓

Answer

Given that,$\mu_\text{r}=1.56,\mu_\text{y}=1.60,$ and $\mu_\text{v}=1.68$
  1. Dispersive power $=\omega=\frac{\mu_\text{v}-\mu_\text{r}}{\mu_\text{y}-1}=\frac{1.68-1.56}{1.60-1}$
$=\frac{0.12}{0.60}=0.2$
  1. Angular dispersion $=(\mu_\text{v}-\mu_\text{r})\text{A}=0.12\times6^\circ=7.2^\circ$

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