Science (086) — AI-generated practice question

(i) Concave Mirror: A ray parallel to the principal axis, after reflection, passes through the principal focus F of the concave mirror. (Law of reflection is obeyed.)

(ii) Convex Lens: A ray parallel to the principal axis, after refraction, passes through the principal focus F₂ on the other side of the convex lens. (Law of refraction is obeyed.)

Ray Diagrams:

```
Concave Mirror: Convex Lens:
→→→→→\ →→→→→|→→→→↘
↘→F | F₂
```
(Students should draw neat labelled diagrams showing the above paths.)

Reason for different behaviour: In a concave mirror, the ray bounces back (reflection) from the curved surface, converging to F in front of the mirror. In a convex lens, the ray passes through the glass (refraction) and bends towards the normal at each surface, converging to F₂ on the other side. One involves reflection; the other involves refraction.

Source: Chapter 9, Sections 9.2.2 and 9.3.5

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• Examiners expect you to clearly state what happens in each case separately and give the reason in terms of reflection vs. refraction.
• Draw simple, labelled diagrams — label the mirror/lens, principal axis, F, and the ray path. Diagrams carry marks.
• Key distinction: mirror obeys laws of reflection (ray stays on same side); lens obeys laws of refraction (ray crosses to other side).
• Avoid writing extra details about image formation — the question only asks about the ray's path and the reason for different behaviour.