Optics Question 584
Question: If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be
[CPMT 1986; MNR 1988; MP PMT 2002; UPSEAT 2000]
Options:
A) 1.5
B) 1.66
C) 1.33
D) 3
Show Answer
Answer:
Correct Answer: C
Solution:
$ f=\frac{R}{(\mu -1)} $
$ \Rightarrow 30=\frac{10}{(\mu -1)} $
$ \Rightarrow \mu =1.33 $ .
