Question

Parallel rays of Sun fall upon a concave lens of 10cm focal length at a distance of 20cm from this lens a convex lens of 15 CM focal length is a place where should the lens we place to get the image of the Sun

Answer 1

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Explanation:

Given that,

Focal length f=15cm

Distance of the image v=−10cm

We know that,

f

1

=

v

1

−

u

1

−15

1

=

−10

1

−

u

1

−

u

1

=

−15

1

+

10

1

−

u

1

=

30

1

u=−30cm

Hence, the object is placed 30 cm away from the concave lans