Two plane mirrors meet at a right angle along a vertical edge

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics

Problem

Two plane mirrors meet at a right angle along a vertical edge. A small light source is positioned 12 cm12\,\text{cm} from each mirror on the line that bisects the 90∘90^{\circ} angle between them. Consider the image that results from two successive reflections—first in one mirror, then in the other. What is the straight-line distance between this double-reflected image and the original light source? (a) 24 cm24\,\text{cm} (b) 242 cm24\sqrt{2}\,\text{cm} (c) 48 cm48\,\text{cm} (d) 122 cm12\sqrt{2}\,\text{cm}

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