Question

Identify the physical quantity that cannot be measured using a spherometer:

• A. Radius of curvature of concave surface
• B. Specific rotation of liquids
• C. Thickness of thin plates
• D. Radius of curvature of convex surface

Answer 1

Answer: (B)

Specific rotation of liquids

Answer 2

A spherometer is an instrument used primarily to measure the curvature of spherical surfaces (both concave and convex) and the thickness of thin plates. It cannot measure properties of liquids, such as specific rotation, which is a measure of the optical activity of a substance in solution.
So, the correct answer is option 2.