Hinged Mirror, Multiple Images - Physics Demonstrations - Hinged Mirror, Multiple Images | Physics Undergraduate Labs

Purpose

Demonstrates how two hinged plane mirrors create multiple images through successive reflections. Students verify the relationship $N = 360°/\theta - 1$ by counting images at various angles, and observe the "true mirror" effect at 90°.

Large hinged front-surface mirrors on a semicircular protractor base, set at approximately 60 degrees with a small light bulb between them showing multiple reflected images

Hinged mirrors set at a wider angle (approximately 90 degrees) on the protractor base, showing fewer reflected images of the light bulb

Hinged mirrors set at a narrower angle on the protractor base, showing more reflected images of the light bulb

Close-up view into the hinged mirrors at a small angle, showing many reflected images of a light bulb arranged in a radial arc

Figure 1: Large hinged mirror apparatus on protractor base, set near 60° with a light bulb object. Multiple reflected images are visible in both mirrors.

Figure 2: Mirrors at a wider angle (~90°) produce fewer images — three are visible, consistent with N = 360°/90° - 1 = 3.

Figure 3: A narrower angle produces more images radiating symmetrically from the hinge line.

Figure 4: Close-up at a small angle showing many images arranged in a radial arc. Each image results from a different number of successive reflections.

Small Hinged Mirror

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