Snell's Law — n₁sin(θ₁) = n₂sin(θ₂)
Drag the incident angle and change media. Watch the ray bend at the boundary.
Incident angle θ₁ 45°
Medium 1 (n₁) Air
Medium 2 (n₂) Glass
n₁sin(θ₁) = n₂sin(θ₂)  →  θ₂ = °
n₁
n₂
θ₁ (incident)
°
θ₂ (refracted)
°
Critical angle
°

θ₂ vs θ₁ (Snell's curve)

Refractive index comparison

Law of Reflection — θᵢ = θᵣ
Angle of incidence always equals angle of reflection. Explore flat and curved mirrors.
Incident angle 40°
Mirror type Flat
θᵢ = θᵣ = °  |   Normal is perpendicular to surface
Incident angle
°
Reflected angle
°
Mirror type

θᵣ vs θᵢ (always equal!)

Multiple reflections path

Thin Lens Equation — 1/f = 1/v + 1/u
Move the object distance. The image forms according to the lens formula. Try diverging lenses too!
Focal length f 20 cm
Object distance u 40 cm
Object height h 30 cm
1/v = 1/f − 1/u  →  v = cm   (m = )
Focal length f
cm
Object dist u
cm
Image dist v
cm
Magnification m
×
Image type

Image distance vs Object distance

Magnification vs Object distance

Electromagnetic Spectrum — c = fλ
Explore wavelength, frequency, and energy across the EM spectrum. c = 3×10⁸ m/s.
Wavelength λ 550 nm
c = fλ  →  f = c/λ = THz  |   E = hf = eV
Wavelength λ
nm
Frequency f
THz
Energy E
eV
Region
Speed c
3×10⁸
m/s

Energy vs Wavelength

EM Spectrum overview