Question

An object is placed at the following distances from a convex lens of focal length $10cm$.
(a) $8cm$ (b) $15cm$ (c) $20cm$ (d) $25cm.$

Which position of the object will produce ..............
i) a diminished, real and inverted image ?
ii) a magnified, real and inverted image ?
iii) a magnified, virtual and erect image ?
iv) an image of same size as the object ?

Justify your answer in each case.

Answer 1

Convex lens forms diminished, real and inverted image for object distance greater than $2f$.

Convex lens forms real, inverted image of same size for object distance equal to $2f$.

Convex lens forms magnified, real and inverted image for object distance between $f$ and $2f$.

Convex lens forms magnified, virtual and erect image for object distance lesser than $f$.

Hence,

for case (i) object distance is $25cm$

for case (ii) object distance is $15cm$

for case (iii) object distance is $8cm$

for case (iv) object distance is $20cm$