Find the focal length of a lens of power – 2.0 D. What type of lens is this?

 

Answer

Given

Power of lens = –2.0 D

 

We know that,

Power of the lens = 1/Focal length

–2 = 1/Focal Length

Focal length = 1/(–2)

Focal length = –0.5 m


Since the focal length is negative, the lens is a concave lens.

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.