Question

A lens produces an image 10cm away from the optical centre. If the magnification
of the image is 1/5, find the focal length of the lens. please answer fast​

Answer 1

Answer:

f = 12.5 cm

Explanation:

m = Height of image h’ / Height of object h

        = Distance of image v / Distance of object u

1/5 = 10 / u

u = 50 cm

Now, 1/v – 1/u = 1/f

          1/10 – 1/50 =1/f

          1/f = 2/25

          f = 25/2 = 12.5 cm (Ans)

Answer 2

Explanation:

The second image is my gf's face after seeing my solution