Q1. [2] medium thorough-understanding
Drivers prefer a convex mirror over a plane mirror as a rear-view mirror even though a plane mirror gives undistorted sizes. Give TWO distinct optical reasons, based on the properties of image formation by a convex mirror, that justify this preference.
Generated by claude-sonnet-4-6 · 2026-06-26 01:12 · grounding rag
Model Answer
- Wider field of view: A convex mirror is curved outwards, so it has a wider field of view than a plane mirror of the same size. The driver can see a much larger area of traffic behind the vehicle.
- Always erect and fully visible image: A convex mirror always forms a virtual, erect, and diminished image for any position of the object. This allows the driver to see a greater area without the image being inverted or cut off.
Source: Chapter 9, Uses of Convex Mirrors
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Explanation
Examiners expect exactly two distinct optical reasons: (i) wider field of view due to outward curvature, and (ii) always erect (never inverted) image regardless of object distance. Both points are explicitly stated in the "Uses of convex mirrors" paragraph. Avoid simply saying "smaller image" as a reason — link it to the consequence (larger area visible). Each reason earns 1 mark.