Question

Where should we keep the object from a convex lens of focal length 18 cm to obtain an equal sized image at 36 cm on the screen kept at the other side of the lens?​

Answer 1

Explanation:

By using lens formula

v

1

−

u

1

=

f

1

where v=24cm ,f=18cm

24

1

−

u

1

=

18

1

from this we get u=−72cm

magnification of lens is m=

u

v

m=

−72

24

=−

3

1