Optics Question 689
Question: The focal lengths of convex lens for red and blue light are 100 cm and 96.8 cm respectively. The dispersive power of material of lens is
[Pb. PET 2003]
Options:
A) 0.325
B) 0.0325
C) 0.98
D) 0.968
Show Answer
Answer:
Correct Answer: B
Solution:
$ \omega =\frac{f _{R}-f _{V}}{f _{y}}=\frac{f _{R}-f _{V}}{\sqrt{f _{V}f _{R}}} $ .
Putting value of $ f _{V} $ and $ f _{R} $ we get $ \omega =0.0325 $ .
