Optics Question 837
Question: A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12 cm below the surface, the radius of this circle (in cm) is -
Options:
A) $ 36\sqrt{5} $
B) $ 4\sqrt{5} $
C) $ 36\sqrt{7} $
D) $ 36/\sqrt{7} $
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ \sin i _{c}=\frac{1}{\mu }=\frac{r}{\sqrt{r^{2}+h^{2}}} $
$ \text{Using }h=12cm,\mu =4/3 $
$ \text{We get }r=\frac{36}{\sqrt{7}}cm. $
