Question

a convex lens of focal length 20 cm is placed at a distance of 25 cm from a wall . calculate the distance from the lens at which an object should be placed so that its distinct real image is form​

Answer 1

Answer:

f=10cm,v=12cm,u=?

We know,

f

1

=

v

1

+

u

1

10

1

=

12

1

−

u

1

u=−60cm

∴The object must be placed at a distance 60cm in front of the lens.

Explanation:

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