WBCS.LIVE practice question

What is the power of a lens whose focal length is 2 meters?

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

Answer options

  1. 2 Dioptre
  2. -0.5 Dioptre
  3. 0.5 Dioptre
  4. 1 Dioptre

Correct answer and explanation

Correct answer: 0.5 Dioptre

Explanation: ✅ Correct Answer: (C) 0.5 Dioptre 📚 Explanation: Step-1: Use the formula for the power of a lens: P = 1 / f, where 'f' is the focal length in meters. Step-2: Here, f = 2 meters. So, P = 1 ÷ 2. Step-3: P = 0.5. The unit of power of a lens is the Dioptre (D). Therefore, the power is 0.5 D.