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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] medium exam-ready
A convex lens of focal length 20 cm is used to form an image of an object placed at 20 cm from it. The image is formed: (A) At 20 cm on the same side as the object (B) At infinity (C) At 40 cm on the other side (D) At 10 cm on the other side
  1. A At 20 cm on the same side as the object
  2. B At infinity
  3. C At 40 cm on the other side
  4. D At 10 cm on the other side
Generated by claude-sonnet-4-6 · 2026-06-26 01:11 · grounding rag
Model Answer

(B) At infinity

When an object is placed at the principal focus (f = 20 cm, u = 20 cm) of a convex lens, the image is formed at infinity.

Explanation

From Table 9.4 (Ch. 9): when the object is placed at focus F₁, the image is formed at infinity. Here, object distance = focal length = 20 cm, so the object is at F₁. This is a standard result students must memorise from the image formation table for convex lenses.

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