Question

You can provided with two lense of focal length 20cm and 30cm respectively these lenses can diverge the light . Which lens while you use to obtain more divergent light ? Name these lenses.

Answer 1

Lense with focal length 20cm because its power is more by the relation.

$f = \frac{1}{p}$

These lenses are called convex lenses.

Hope my answer will help you..:)

Answer 2

Explanation :

It is given that,

Focal length of the first lens, $f_1=20\ cm$

Focal length of the other lens, $f_2=30\ cm$

We know that power of the lens is given by :

$P=\dfrac{1}{f}$

So, the lens having less focal length has more power as compared to the other lens.

To obtain more divergent light a lens with focal length of 20 cm is used.

Concave lens are also known as diverging lens.