In the visible region of the spectrum the rotation of the place of polarization is given by 2 b a .

Question

In the visible region of the spectrum the rotation of the place of polarization is given by θ =a+ b/λ²  a . The optical rotation produced by a particular material is found to be 30° per mm at λ=5000 Å and 50° per mm at  λ=4000 Å . The value of constant a will be 

(A) +50°/9  per mm

(B) -50°/9per mm

(C) +9°/50 per mm

(D) -9°/50per mm 

Answer 1

Correct option- (B) -50⁰/9 per mm

Explanation:-