WBCS.LIVE practice question

What is the standard SI unit used to measure the power of a lens?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. Candela
  2. Lumen
  3. Dioptre
  4. Watt

Correct answer and explanation

Correct answer: Dioptre

Explanation: āœ… Correct Answer: C) Dioptre šŸ“š Explanation: The power of a lens is mathematically defined as the reciprocal of its focal length measured in meters (P = 1/f). A lens with a focal length of 1 meter has a power of exactly one dioptre. In clinical practice, a convex lens is assigned a positive dioptre value, while a concave lens is assigned a negative value.