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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 thorough-understanding
Assertion (A): A person with presbyopia may need bi-focal lenses that combine both a concave and a convex portion. Reason (R): Presbyopia can involve simultaneous difficulty in seeing both distant and nearby objects clearly.
  1. A Both A and R are true, and R is the correct explanation of A.
  2. B Both A and R are true, but R is not the correct explanation of A.
  3. C A is true but R is false.
  4. D A is false but R is true.
Generated by claude-sonnet-4-6 · 2026-06-26 01:09 · grounding rag
Model Answer

Option A — Both A and R are true, and R is the correct explanation of A.

A presbyopic person may suffer from both myopia and hypermetropia simultaneously, requiring bi-focal lenses with a concave portion (for distant vision) and a convex portion (for near vision). R correctly explains why A is true.

Source: Chapter 10, Section 10.2(c) – Presbyopia

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Explanation

The textbook explicitly states that a person suffering from both myopia and hypermetropia (which can occur with presbyopia) often requires bi-focal lenses consisting of concave (upper, for distant vision) and convex (lower, for near vision) portions. The Reason directly and correctly explains why bi-focal lenses are needed — hence Option A is correct, not B. Students often confuse presbyopia with only one defect; remember it can involve both.

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