Question

A convex lens has a focal length of 30 cm. Calculate its power....
solve my dear frnds..

Answer 1

⭐⭐⭐⭐⭐ ANSWER ⭐⭐⭐⭐⭐

➡ This type of numerical is generally very easy to work-out.

➡ Formulas should be remembered carefully.

➡ Here, we will apply the formula :- Power of a convex lens = 1/focal length(in metre).

=================================

So, Here, 30 cm = 0.3 m

Power = (1/0.3) D = 3.33 D

Hence, option (2) is your answer.

==================================

⭐⭐⭐ ALWAYS BE BRAINLY ⭐⭐⭐

Answer 2

we know that ,
power=1/focal length

given,

focal length =30 cm

= 0.3m


now, power = 1/0.3

= 3.3 D



hope it helps you .