Optics Question 727
Question: For a colour of light the wavelength for air is $ 6000{AA} $ and in water the wavelength is $ 4500{AA} $ . Then the speed of light in water will be
Options:
A) $ 5.\times 10^{14}m/s $
B) $ 2.25\times 10^{8} $ m/s
C) $ 4.0\times 10^{8} $ m/s
D) Zero
Show Answer
Answer:
Correct Answer: B
Solution:
$ v\propto \lambda \Rightarrow \frac{v _{1}}{v _{2}}=\frac{{\lambda _{1}}}{{\lambda _{2}}} $
$ \therefore $ $ v _{2}=\frac{v _{1}}{{\lambda _{1}}}\times {\lambda _{2}}=3\times 10^{8}\times \frac{4500}{6000}=2.25\times 10^{8} $ m/s
