Question

An object is gradually moved from infinity up to a convex lens. State bow do
the position, size and nature of the image formed by the convex lens change?​

Answer 1

Answer:

When in a convex lens object is moved from infinity to be kept at a finite distance 5 cases of image formation occur. ( Taking centre of curvature on left side as C1 and centre of curvature on right side as C2. Also the left side focus if F1 and right side focus is F2)

1) When object is just beyond C1

Location of image: Between F2 and C2.

Nature- Real and inverted

Size- Slightly diminished

2) When object is at C1:

Location- At C2

Nature- Real and inverted

Size- Same size

3) When object is between F1 and C1:

Location- Beyond C2

Nature- Real and inverted

Size- Enlarged

4) When object is at F1-

Location- At infinity

Size- Real and inverted

Nature- Highly enlarged

5) When object is between O and F1

Location - At C1 ( Same Side)

Size- Enlarged

Nature-Virtual and erect