Question

8. A convex lens of focal length 15 cm forms an
image 10 cm from the lens. How far is the object
placed from the lens? *​

Answer 1

correction -> lens = concave

Lens formula = 1/v - 1/u = 1/f

f = -15 cm

v = -10cm

1/10 - 1/u = 1/15

-1/u = -1/15 + 1/10

-1/u = 1/30

u = -30

so the distance of object from the lens is 30cm