Optics Bench: Refraction & Total Internal Reflection
A real optics bench: drag the ray box around a protractor and watch Snell's law solved live. Wavefronts visibly slow down and squeeze together in the denser medium, the reflected ray brightens as you approach the critical angle, and beyond it the light undergoes total internal reflection. Record your own (sin i, sin r) data points and measure the refractive index from the gradient — exactly like the glass-block practical.
Drag the ray box to change the angle of incidence. Green ticks are wavefronts — watch them squeeze together in the slower medium. Dashed red line = critical angle (when it exists).
Set an angle, press Record point, repeat for 5+ angles. The gradient of your line is n₁/n₂ — exactly how the glass-block practical works.
Angle of incidence. Angle between the incoming ray and the normal, in degrees.
Angle of refraction. Angle between the refracted ray and the normal, in degrees.
Refractive index. How much a medium slows light down: n = c/v. Air ≈ 1.00.
Critical angle. The angle of incidence for which r = 90°. Beyond it, total internal reflection.