Convex Lens and Lamp - Physics Demonstrations - Convex Lens and Lamp | Physics Undergraduate Labs

Ensure the lamp cord does not create a tripping hazard across the demonstration area. Use a switched outlet or power strip that allows you to control the lamp from the demonstration position. Allow the lamp to cool before handling if repositioning is needed.

Purpose

A large convex lens (f = 220 cm) projects a real, inverted image of a lamp filament onto a screen. Students directly observe real image formation and can verify the thin lens equation with measured distances.

Lecture hall with translucent screen on left showing inverted real image of a glowing lamp filament, large convex lens on tripod in center, and boxed lamp visible in background right

Figure 1: The demonstration shows real image formation as the lamp filament is projected onto the screen. The large convex lens (f = 220 cm) creates an inverted, real image that can be clearly viewed by the class.

Carbon Filament Lamp in Shielded Box

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Convex Lens on Tripod

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Safety Warnings

Warning: Electrical Safety

Purpose