Solve this.
Q.14. 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 0.25 m and an optical rotation of 0.4 rad is observed. The percentage of purity of sugar in the sample is .............
1) 80 %
2) 89 %
3) 11 %
4) 20 %