Question

The power of a convex lens of focal length 25 cm is​

Answer 1

Explanation:

power = 1/0.25 = 4D......

Answer 2

The power of the convex lens is 4D.

• Given data :

The focal length of the given convex lens is 25 centimetres or 0.25 metres. (Term of unit conversion is 100 centimetres = 1 metre)

(We converted the focal length into metre because,metre is the SI unit of the length and rest of the calculations will be performed by SI units)

• Now,we have to calculate the value of the power of the given convex lens by the help of the following mathematical formula :

Power of the lens = 1/focal length

= 1/0.25

= 4 D

So,the power of the given lens is 4D. (Here,the "D" is dioptre which is the SI unit of power of a lens).