Q. Light passes successively through two polarimeter tubes each of length $0.29m$. The first tube contains dextro rotatory solution of concentration $60kgm^{- 3}$ and specific rotation $0.01rad\ m^{2}kg^{- 1}$. The second tube contains laevo rotatory solution of concentration $30kg/m^{3}$ and specific rotation $0.02radm^{2}kg^{- 1}$. The net rotation produced is
A) $15{^\circ}$
B) $0{^\circ}$
C) $20{^\circ}$
D) $10{^\circ}$
Explanation
(b) Rotation produced $\theta = Sic$
Net rotation produced $\theta_{r} = \theta_{1} - \theta_{2} = l(S_{1}c_{1} - S_{2}c_{2})$
$= 0.29 \times \lbrack 0.01 \times 60 - 0.02 \times 30\rbrack = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.