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Question: Answered & Verified by Expert
The refractive index of a particular material is $1.67$ for blue light, $1.65$ for yellow light and 1.63 for red light. The dispersive power of the material is
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Options:
  • A $0.0615$
  • B $0.024$
  • C $0.031$
  • D $1.60$
Solution:
2246 Upvotes Verified Answer
The correct answer is: $0.0615$
Given, refractive index for blue light, $\mu_{b}=1.67$
Refractive index for yellow light, $\mu_{y}=1.65$
Refractive index for red light, $\mu_{r}=1.63$
Dispersive power, $\omega=$ ?
Dispersive power is the ratio of angular dispersion and mean deviation.
The formula of dispersive power is given as
$$
\begin{aligned}
\omega &=\frac{\mu_{b}-\mu_{r}}{\mu_{y}-1} \\
&=\frac{1.67-1.63}{1.65-1} \\
&=\frac{0.04}{0.65}=0.0615
\end{aligned}
$$

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