Converging Lens
(f > 0) Object beyond 2F: Real, inverted, diminished image between F and 2F
Lens Refraction Calculator
Calculate image formation through lenses with ray diagrams
Ray diagram
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Ray diagram description.
Results
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Theory & Formula
Lens refraction describes how light rays bend when passing through converging or diverging lenses.
Lens Types:
- Converging (Convex): Thicker at center, positive focal length, converges parallel rays
- Diverging (Concave): Thinner at center, negative focal length, diverges parallel rays
Sign Convention (Cartesian):
- Distances measured from optical center of lens
- Real images: v > 0 (opposite side from object)
- Virtual images: v < 0 (same side as object)
- Inverted images: m < 0
- Upright images: m > 0
Power of Lens: P = 1/f (in meters), measured in diopters (D)
\(\frac{1}{f} = \frac{1}{v} + \frac{1}{u}, \quad m = \frac{v}{u} = \frac{h'}{h}\)
Worked Examples
Converging Lens
Object between F and 2F: Real, inverted, magnified image beyond 2F
Diverging Lens
(f < 0) Always forms virtual, upright, diminished image on same side
External educational resource
Explore lenses and mirrors in PhET
Open PhET's Geometric Optics simulation to drag a lens or mirror, move the object, and watch the image form in real time.
PhET Interactive Simulations, University of Colorado Boulder