Question

Find the power of a convex lens if the image formed is at a distance of 20 cm from the lens when the object is placed on the other side of the lens at 25 cm from the optical centre?
A) 1 diopters B) -9 diopters C) 9 diopters D) -1 diopters

Answer 1

Answer:

D) -1 diopters

Explanation:

u = -20

v = 25

1/f = 1/u+ 1/v

1/f = 1/25 - 1/20

1/f = 4-5/100

1/f = -1/100

f = -100 cm

f = -1 m

power = 1/f

power = -1 diopters

hope this helps