Presentation on theme: " The amount of refraction in a material can be determined using the index of refraction.index of refraction The index of refraction can be used to."— Presentation transcript:
The amount of refraction in a material can be determined using the index of refraction.index of refraction The index of refraction can be used to calculate the speed of light in that material. The greater the index of refraction, the more the speed of light will slow down in that material.
ratio of the speed of light in a vacuum to the speed of light in a medium speed of light in air almost as fast as vacuum so it is 1.00 the higher the value, the more it will slow down n = index of refraction c = speed of light in a vacuum = 3.0 x 10 8 m/s v = speed of light in a substance (m/s) index of refraction also found by measuring the angles of incidence and refraction and calculating sin n = sin ∠i sin ∠R
12-4 Sample Problem 1 12-4 Sample Problem 1 12-4 Sample Problem 2 12-4 Sample Problem 2 Material Index of Refraction (n)
when light travels from one medium to another some of the light is reflected and some is refracted (bent) the refraction and reflection happen at the same time. called partial reflection and refraction. ex. looking at pond or through a window reflected ray refracted ray incident ray
when light speeds up as it enters another medium, ∠ R is greater than ∠ i as ∠ i increases, refracted ray will travel along boundary between 2 media ∠ i now the critical angle and ∠ R is 90 o if ∠ i increases even more, all light will be reflected back to 1 st medium = Total Internal Reflection Refraction of Light Refraction of Light