RRB Technician 2013 Ques 19
Question: $ _{a}{\mu_g}=\frac{3}{2} $ and $ _{a}{\mu_w}=\frac{4}{3} $ . If the speed of light in glass is $ 2.00\times 10^{8}m/s, $ the speed in water will be
Options:
A) $ 2.67\times 10^{8}m/s $
B) $ ~2.25\times 10^{8}m/s $
C) $ 1.78\times 10^{8}m/s $
D) $ 1.50\times 10^{8}m/s $
Show Answer
Answer:
Correct Answer: B
Solution:
- $ _{a}{\mu_g}=\frac{V _{a}}{V _{g}} $
$ \Rightarrow $ $ \frac{3}{2}=\frac{V _{a}}{2\times 10^{8}}\Rightarrow V _{a}=3\times 10^{8}m/s $
$ \Rightarrow $ $ \frac{4}{3}=\frac{3\times 10^{8}}{V _{w}} $
$ \Rightarrow $ $ V _{w}=\frac{9}{4}\times 10^{8}=2.25\times 10^{8} $ $ _{a}{\mu_g}=\frac{V _{a}}{V _{g}} $
$ \Rightarrow $ $ \frac{3}{2}=\frac{V _{a}}{2\times 10^{8}}\Rightarrow V _{a}=3\times 10^{8}m/s $
$ \Rightarrow $ $ \frac{4}{3}=\frac{3\times 10^{8}}{V _{w}} $
$ \Rightarrow $ $ V _{w}=\frac{9}{4}\times 10^{8}=2.25\times 10^{8} $
BETA
