Question

Light passes successively through two polarimeter tubes each of length 0.29 m. The first tube contains dextro-rotatory solution of concentration $60kg{m}^{-3}$ and specific rotation 0.01 rad $m^{2}k{g}^{-1}$. The second tube contains laevo-rotatory solution of concentration $30kg{m}^{-3}$ and specific rotation 0.02 rad $m^{2}k{g}^{-1}$. The net rotation produced is

• A. 15${}^{\circ }$
• B. 0${}^{\circ }$
• C. 20${}^{\circ }$
• D. 10${}^{\circ }$

Answer 1

Answer: (B)

$Using\theta =SIC,eget,{\theta }_{1}and{\theta }_{2}bothequalto0.01\times 0.29\times 60\therefore Delta\theta =0$