Science (086) — AI-generated practice question

When a ray travels parallel to the principal axis and strikes a convex mirror, it reflects such that the reflected ray appears to diverge from the principal focus F, which lies behind the mirror. An observer in front sees the reflected ray coming from F. The convex mirror thus acts as a diverging mirror.

By the law of reflection, the normal at any point on a spherical mirror passes through its centre of curvature C. For a convex mirror, C lies behind the reflecting surface, so the normal points outward. Applying the angle of incidence = angle of reflection to this geometry causes the reflected ray to spread away from the axis.

For a concave mirror, C lies in front of the surface; the geometry of the normal directs the reflected ray to actually converge at F in front of the mirror, making it a converging mirror.

Source: Chapter 9, Section 9.2 – Spherical Mirrors

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• Examiners want: (1) path of reflected ray for convex mirror (diverges, appears to come from F behind mirror), (2) reference to law of reflection (∠i = ∠r, normal through C), (3) contrast with concave mirror (converges at F in front).
• Key distinction: the position of C (behind for convex, in front for concave) determines whether the normal tilts the reflected ray inward or outward.
• Don't write "virtual focus" in isolation — say "appears to come from F behind the mirror" to show you understand it's virtual.
• Avoid over-explaining; 3 marks = ~3 clear points.