Find the Power of a Concave Lens of Focal Length 2m

By BYJU'S Exam Prep

Updated on: September 25th, 2023

The power of a concave lens of focal length 2m is -0.5D.

Step1: Given that focal length ( f ) = 2m

Step2: Concave lens

A straight beam of light is diverted by this kind of lens into an upright, virtual image known as a concave lens.
Both actual and virtual images can be created by this kind of lens.
The focal length of a concave lens is always negative in accordance with the sign convention.

Step3: Now we have to calculate the power of the concave lens

The power of the lens can be calculated as

P=-1/f [where ‘P’ is power and ‘f’ is focal length]

Subatituting the value of f in above equation we get

According to the sign convention, the focal length of a concave lens is always negative.

P=1/-2

P=-0.5D

Hence, the power of a concave lens of focal length 2m is -0.5D

Table of content

1. Find the Power of a Concave Lens of Focal Length 2m

Concave lens

A concave lens is one that bends a straight light beam away from the source and focuses it into a distorted, upright virtual image. Both actual and virtual images can be created using it. At least one internal surface of concave lenses is curved. Since it is rounded at the centre and bulges outward at the borders, a concave lens is also known as a diverging lens because it causes the light to diverge. Since they make distant objects appear smaller than they actually are, they are used to cure myopia.

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