1. Air Liquid A question based on refractive index, Snell’s law, total internal reflection, and some geometry

2. Grazing emergen ce Parallel lines

4. Air Liquid Snell’s law for the relationship between the angle of incidence and the angle of refraction for a light ray travelling FROM AIR to LIQUID. Angle of incidence Angle of refraction Refractive index for light going from AIR to LIQUID The light is REFRACTED towards the normal. Normal Background notes and thinking

5. Air Liquid Snell’s law for the relationship between the angle of incidence and the angle of refraction for a light ray travelling FROM LIQUID to AIR. Refractive index for light going from AIR to LIQUID Refractive index for light going from LIQUID to AIR Background notes and thinking

6. Air Liquid The source is the green light in the liquid, so that we swap the angles round, if we take the reciprocal or inverse of the refractive index. This is the principal of reversibility. As the angle of incidence increases, the angle of refraction increases still more. Background notes and thinking

7. Air Liquid As the angle of incidence increases, the angle of refraction increases still more. Background notes and thinking

8. Air Liquid At the CRITICAL ANGLE of incidence, the ray JUST ESCAPES from the surface. Background notes and thinking