Optics Question 183
Question: Specific rotation of sugar solution is 0.01 SI units. 200 $ kg{{m}^{-3}} $ of impure sugar solution is taken in a polarimeter tube of length 0.25m and an optical rotation of 0.4rad is observed. The percentage of purity of sugar is the sample is
[KCET 2004]
Options:
A) 80%
B) 89%
C) 11%
D) 20%
Show Answer
Answer:
Correct Answer: A
Solution:
Specific rotation $ (\alpha )=\frac{\theta }{lc}\Rightarrow c=\frac{\theta }{\alpha l}=\frac{0.4}{0.01\times 0.25}=160kg/m^{3} $
Now percentage purity of sugar solution $ =\frac{160}{200}\times 100=80% $
