Question

The Focal Length of a convex lens is 20cm. what is its powers?​

Answer 1

Answer:

The power of the convex lens is SD.

Solution

Given: Focal length (f)=20 cm =0.2 m

To find: Power of the lens (P)

Formula: P=1f(m)

Calculation: From formula,

P=10.2

=5D

Answer 2

Answer:

power of convex lens is +5 D

Explanation:

given

focal length of convex lens f=20 cm

change it into meter

f= 20/100 = 1/5 meter

formula

power of lens = $\frac{1}{focal length (in meter)}$

power of lens = 1/(1/5)

power of lens = + 5 D