Question

Pick the correct answer from the following two statements:
a) A lens has at least one curved surface.
b) A plano-concave lens has two curved surfaces.

• A. Only (a) is true
• B. Only (b) is true
• C. Both (a) and (b) are true
• D. Both (a) and (b) are false

Answer 1

The Correct Option is A

Correct answer: Only (a) is true

Explanation: 
Statement (a): A lens has at least one curved surface.
This is true. By definition, a lens is made from a transparent material with at least one surface that is curved (either convex or concave) to refract light. 

Statement (b): A plano-concave lens has two curved surfaces.
This is false. A plano-concave lens has one flat (plano) surface and one inwardly curved (concave) surface. 

Hence, only (a) is true.