Science (086) — AI-generated practice question

Concave Mirror (object at C, i.e., distance = 2f):
From Table 9.1, the image forms at C itself (distance = 2f in front of mirror). The image is same size as the object, and real and inverted.

Convex Lens (object at 2f):
From the lens ray diagrams (Fig. 9.16), the image forms at 2f on the other side. The image is same size as the object, and real and inverted.

Comparison: Both cases produce an image that is real, inverted, and of the same size as the object, formed at a distance 2f from the optical element.

Reason: In both cases the object is placed at the centre of curvature / twice the focal length (2f). This is the symmetric point for both a concave mirror and a convex lens, so refracted/reflected rays reconverge at the same distance 2f, producing a 1:1 image.

Source: Chapter 9, Section 9.2.1 (Table 9.1) and Section 9.3.5 (Fig. 9.16)

---

• The table (Table 9.1) directly states: object at C → image at C, same size, real and inverted.
• For the convex lens, placing the object at 2f is the standard case (Exercise Q3 confirms same-size image at 2f).
• Examiners award marks for: correct position (2f / at C), correct size (same), correct nature (real, inverted), and the comparative/reasoning point.
• Keep the comparison explicit — don't just describe each case separately.