The image of an object placed in front of a concave lens is formed at 10 cm. If the focal length of lens is 15cm then calculate distance of object from lens.

Given

Distance of image from concave lens = -10cm (as in case of concave lens, image is always virtual)

Focal length of concave lens = -15cm (focal length of concave lens is always negative)

Formula used

Lens Formula

Using lens formula

U = -30cm

The distance of object from the lens is 30cm