Term 2 Week 9 2019

Homework

• Ex 3I, p.85-87 Wave Refraction on a String
• Ex 3B, p. 47-52, Refraction

Snell's Law & Critical Angle

The Critical Angle occurs when a wave is attempting to pass from a medium with a slower speed to that of a higher speed 

low v → higher v

low 𝜆 → higher 𝜆

high n → lower n

The Critical angle is the incident angle where the refracted angle equals 90 degrees

• Any incident above the Critical angle will prevent any refraction occuring and Total Internal Reflection will occur
• The Critical angle is can be found by sin(𝜭c) = n2/n1

FibreOptic Cables: How they work?

Total Internal Reflection T.I.R.

What Happens to Lazers Underwater?