Science (086) — AI-generated practice question

(i) The negative sign indicates that the image is real and inverted.

(ii) Using $m = -\dfrac{v}{u}$, with $m = -3$ and $u = -10$ cm:

$$-3 = -\frac{v}{-10} \Rightarrow -3 = \frac{v}{10} \Rightarrow v = -30 \text{ cm}$$

Image distance = –30 cm (30 cm in front of the mirror).

(iii) The mirror is concave. It forms a real, enlarged image (|m| = 3 > 1) of an object placed in front of it, which is a property of a concave mirror.

Source: Chapter 9, Section 9.2.4 — Mirror Formula and Magnification

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• A negative magnification always means real and inverted (stated explicitly in the textbook).
• Use $m = -v/u$; remember $u$ is negative by sign convention (object in front).
• A convex mirror always gives virtual, diminished images (m < 1 in magnitude), so a real, enlarged image can only be produced by a concave mirror — examiners expect this justification.