Question

Focal length of concave lens is 20 cm. Find its power.​

Answer 1

Answer:

p=1/f

p=1/(20/100)

p=5d

Answer 2

Answer:

f=1/D

D=1/f

Given:

f=-20 cm=> -0.2 m

D= -1/0.2

=> -5 D

Explanation:

hope it helps...