Generated by claude-sonnet-4-6 · 2026-06-15 06:52 · grounding rag
Model Answer
(a) Ray Diagram:
- Ray 1: Parallel to principal axis → after reflection, passes through F (focus).
- Ray 2: Directed towards centre of curvature C → reflects back along the same path.
- The two reflected rays diverge; extend them behind the mirror (dashed lines). They appear to meet behind the mirror between P and C, giving a virtual image A′B′.
(b) Nature, Position and Size of Image:
- Position: Behind the mirror, between P and C.
- Nature: Virtual and erect.
- Size: Enlarged (magnified), larger than the object.
(This occurs when object is placed between P and F of a concave mirror.)
(c) Sign of Image Distance:
The image is formed behind the mirror (on the same side as the object in a concave mirror's convention). By Cartesian sign convention, this distance is positive (+).
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Explanation
- (a) Examiners check that Ray 1 reflects through F and Ray 2 reflects back on itself through C; dashed lines behind the mirror show virtual image formation correctly.
- (b) This is the standard case: object between P and F of a concave mirror → virtual, erect, magnified image behind the mirror (as in Exercise Q2 of the chapter).
- (c) In Cartesian convention, distances measured in the direction of incident light (in front of mirror) are negative; behind the mirror is opposite to incident light, so image distance v is positive.