Question

CBSE 2016
Find the power of convex lens which
forms a real and inverted image of
magnification - 1 of an object placed at a
distance of 20 cm from its optical centre.​

Answer 1

Plz Thank me

Explanation:

Given magnification m=−1 and object distance u=−20cm

We know magnification m=

u

−v

v=−mu=(−1)(−20)=20cm

Now from lens formula we have,

v

1

−

u

1

=

f

1

20

1

−

20

−1

=

f

1

f=10cm

Now powerp=

f

1

=

100

10

1

=10 D