Question

Find the focal length of a lens of power - 2.0 D. What type of lens is this?

Answer 1

Hola!!
Here's your answer.

✴ Power of a given lens = -2.0 Dioptre.

✴ AS PER THE FORMULA ,
Power = 1/Focal Length.

✳ P = 1/f.
✳ -2.0 = 1/f.
✳ f = 1/-2 = -0.5m.

✴ IT IS A DIVERGING LENS OR CONCAVE LENS.

Hope it helps!!
@charlie16.

Answer 2

Dear Student,

◆ Answer -

Focal length = -50 cm

Type of lens = Concave

● Explanation -

# Given -

Power of lens = - 2 D

# Solution -

Formula for power of the lens ia given by -

Power of lens = 1 / focal length

Substitute value,

-2 = 1 / focal length

Focal length = -1/2

Focal length = -0.5 m

Focal length = -50 cm

Therefore, focal length of lens is -50 cm and it is a concave lens (d/t negative power).

Hope this helps you...