WBCS.LIVE practice question

The power of lens is 4 diopters at focal length will be -

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

Answer options

  1. 20 cm
  2. 25 cm
  3. 50 cm
  4. 400 cm

Correct answer and explanation

Correct answer: 25 cm

Explanation: āœ… Correct Answer: B) 25 cm šŸ“š Explanation: The power of a lens ($P$) in diopters is related to its focal length ($f$) in meters by the inverse formula $f = 1 / P$. The power is given as 4 diopters. Calculation: $f = 1 / 4 = 0.25\text{ meters}$. To convert this measurement into centimeters, we multiply by 100, which yields exactly 25 cm.