Question

A converging lens has a focal length of 25 cm. Calculate its power and express it according to sign convention. ​

Answer 1

Answer:

pls mark me the brainliest

Explanation:

What is the power of a convex lens if the focal length is 25 cm?

Power is expressed as the inverse of focal length, where a focal length of 1 meter is equal to one diopter. So a 25 cm. focal length (0.25 meters) has a power of 4 diopters.

Answer 2

Given:

A converging lens has focal length of 25 cm.

To find:

Power of the lens

Calculation:

General expression of power of a lens is :

$\boxed{ \sf{P = \dfrac{1}{focal \: length \: in \: metres} }}$

Being a converging lens , its focal length will be positive in nature.

Focal length = 25 cm = 0.25 m ;

Putting the values ;

$\sf{\therefore \:P = \dfrac{1}{focal \: length \: in \: metres} }$

$\sf{ = > P = \dfrac{1}{0.25} }$

$\sf{ = > P = \dfrac{100}{25} }$

$\sf{ = > P = + 4 \: dioptre}$

So, final answer is:

$\boxed{ \red{ \large{\rm{Power = + 4 \: dioptre}}}}$