Aim: How can we explain Snell’s Law?

Aim: How can we explain Snell’s Law? Do Now: What is the speed of light in zircon?

Refraction • Waves that are transmitted through a boundary often change direction when entering the new medium. This bending of the path of waves is called REFRACTION. Light Wave Air Water Transmitted Ray is Refracted

Optics Demo

Effects of Refraction

Snell’s Law

A beam of light strikes a crown glass block at an angle of 60o. What is the angle of refraction? n1sinθ1 = n2sinθ2 (1.00) sin (60o) = (1.52) sin θ2 sin θ2 = (1.00) sin (60o) (1.52) θ2 = 35o

An incident ray in lucite is refracted through water. If the incident ray is at an angle of 50o, what is the angle of refraction? n1sinθ1 = n2sinθ2 (1.50) sin (50o) = (1.33) sin θ2 sin θ2 = (1.50) sin (50o) (1.33) θ2 = 60o

Less Dense to More Dense • Light is traveling from a FASTER to a SLOWER medium • The light will bend towards the normal. • Ex: Air to water

More Dense to Less Dense • Light is traveling from a SLOWER to a FASTER medium • The light will bend away from the normal line. • Ex: Water to Air

But what if the light is not entering the new medium at an angle? THE LIGHT WILL NOT BEND!! Air Water No Refraction

Relationship between v and λ • FREQUENCY IS CONSTANT v = fλ • v increases  λincreases • v decreases  λdecreases

As a monochromatic beam of light passes obliquely from flint glass into water, how do the characteristics of the beam of light change? • Its wavelength decreases and its frequency decreases. • Its wavelength decreases and its frequency increases. • Its wavelength increases and it bends toward the normal. • Its wavelength increases and it bends away from the normal.

Trace the path of the ray θ If a ray exits to the same material it started in, the incident angle is equal to the final refracted angle! Flint glass Lucite Diamond θ

Aim: How can we explain Snell’s Law?