Question

Optically active substances are those which
A. Produces polarized light
B. Rotate the plane of polarization of polarized light
C. Produce double refraction
D. Convert the plane polarized light into circularly polarized light

Answer 1

Hint: It simply means the light interaction with matter. Optical activity is any form of polarization dependence on the interaction between light and matter. This interaction is happening due to the presence of chiral compounds.

Complete step-by-step answer:
Optically active polarimetry is a method that measures the interaction between a compound and plane polarized light. This measures the rotation of the polarized light as it passes through an optically active compound. This technique can measure the direction of vibration of polarized light when interacting with an optically active compound. A substance is said to be optically active if it rotates the plane of polarization of polarized light. The substance that can rotate the plane to the clockwise direction are known as dextrorotatory and the substance which can rotate the plane of polarization to the counter clockwise is known as levorotatory. Chiral compounds are the reason behind this rotation of plane polarized light.
Hence the option B is correct.

Additional information:
According to the wave theory of light, an ordinary light vibrates in all planes perpendicular to the propagation. If this ordinary light passes through a polarizer, the emergent ray has vibration only in one plane. This light with motion in one plane is known as plane polarized light.
The magnitude of rotation of optical activity depends on;
i. Nature of the substance
ii. Length of the liquid column through which the light passes
iii. Temperature of the solution
iv. Wavelength of the light
v. Concentration of the solution

Note: Optically active substances can find out by using polarized light. Double refraction occurring when light ray incident on the birefringent materials. It is split by polarization into two rays and they will take different paths. Circular polarization can be observed in electrodynamics. In this, the electromagnetic field of the wave possesses the same magnitude but rotates at a constant rate to the direction of the wave.