Lens Physics Calculator & Simulator
Interactive demonstration of lens power, refractive index, and focal length calculations
Power Calculator: P = 1/f
Power:
+2.00 D
Lens Type:
Converging
Formula Steps:
1. Power formula: P = 1/f
2. Where f is focal length in meters
3. P = 1/0.50 = +2.00 diopters
4. Positive power indicates converging lens
Refractive Index Calculator: 1/f = (n-1)(1/R₁ - 1/R₂)
Refractive Index:
1.50
Material:
Crown Glass
Formula Steps:
1. Lens maker's formula: 1/f = (n-1)(1/R₁ - 1/R₂)
2. Rearrange to solve for n: n = 1 + 1/[f(1/R₁ - 1/R₂)]
3. n = 1 + 1/[0.12(1/0.10 - 1/(-0.15))] = 1.50
4. This matches typical values for crown glass
Medium Change Calculator
New Focal Length:
78.2 cm
Change:
+291%
Formula Steps:
1. Formula: f₂/f₁ = (n_lens - n₁)/(n_lens - n₂)
2. Where n₁ = old medium, n₂ = new medium
3. f₂ = 20.0 × (1.50 - 1.00)/(1.50 - 1.33) = 78.2 cm
4. Focal length increases significantly in water
Physics Summary
Power Calculation
Power P = 1/f measures the converging strength of a lens. Positive power indicates a converging lens, negative power indicates a diverging lens. Units are diopters (D) when focal length is in meters.
Lens Maker's Formula
The lens maker's formula 1/f = (n-1)(1/R₁ - 1/R₂) relates focal length to the lens material's refractive index and the radii of curvature of both surfaces.
Medium Effect
When a lens is moved from one medium to another, its focal length changes according to the relative refractive indices. This explains why underwater vision is affected.
