Science (086) — AI-generated practice question

As an object moves from far beyond 2F₁ towards F₁ along the principal axis of a convex lens, the real image shifts progressively farther from the lens, and its size continuously increases.

Position changes (from Table 9.4):

| Object position | Image position |
|---|---|
| Far beyond 2F₁ | Just beyond F₂ (highly diminished) |
| Beyond 2F₁ | Between F₂ and 2F₂ |
| At 2F₁ | At 2F₂ |
| Between F₁ and 2F₁ | Beyond 2F₂ |
| At F₁ | At infinity (no image formed) |

Size changes: The image starts highly diminished (point-sized when object is at infinity), becomes diminished, then same size as the object (at 2F₁), then enlarged, and finally the image would not be formed as the object reaches F₁.

Throughout this journey, all images are real and inverted. As the object moves closer to F₁, the image moves farther away and grows larger, because the refracted rays become more nearly parallel, requiring a greater distance to converge.

Source: Chapter 9, Section 9.3.4 — Image Formation by Lenses (Table 9.4)

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• Examiners expect you to trace the image position and size systematically through all five object positions from Table 9.4. Missing any position loses marks.
• Mentioning that images are real and inverted throughout (until F₁) is essential — it's a key characteristic the examiner checks.
• The brief justification (rays becoming nearly parallel near F₁ → image at infinity) shows understanding beyond rote memory, which earns full marks on a 5-mark question.
• A small table is acceptable and saves words while covering all positions clearly.