Question

A concave lens of focal length 20 cm forms an image 15 cm from the lens. How far is
the object placed from the lens?
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Answer 1

Answer:

distance between object and lens is 60cmon the left of lens.

Explanation:

As per studies of lenses the there will be the distance of 60cm only on left side of the lens

Answer 2

Answer:

f = -20 cm

v = -15 cm

lens formula :- 1/v - 1/u = 1/f

1/-15 - 1/u = 1/-20

-1/u = 1/15 - 1/20

-1/u = 1/60

1/u = -1/60

u = -60

Object distance is 60 cm towards the left of the lens.