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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] straightforward thorough-understanding
A convex lens of focal length 20 cm is used as a simple magnifier. State the range of object distances for which this lens acts as a magnifier, and explain why the image formed in this case cannot be caught on a screen.
Generated by claude-sonnet-4-6 · 2026-06-26 01:15 · grounding rag
Model Answer

The object must be placed between the focus F₁ and the optical centre O (i.e., within 20 cm from the lens). The image formed is virtual and erect, meaning light rays only appear to diverge from it and do not actually meet — hence it cannot be caught on a screen.

Explanation

For a convex lens to act as a magnifier, the object must be within the focal length so the image is virtual, enlarged, and erect (Table 9.4). A virtual image is formed by the apparent intersection of diverging rays, not real convergence of light, so no screen can capture it. Examiners expect both the range (between F and O) and the reason (virtual image).

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.