Announcements Waves Pt 2. Exam on Monday (18 MC, 2 FR) TC due Tomorrow

Bouncing Beams and Sticky Glass 5.2.2 Reflection/Refraction

Reflection Equation normal incident ray reflected ray θi θr Waves that change mediums or hit boundaries obey the Law of Reflection. Angles are always measured from the normal!

Refraction: Quick Summary https://www.youtube.com/watch?v=FOwDgpKTqdY

Refraction Equation Snell’s Law incident ray normal θi or θ1 reflected ray θr Less dense  More dense = toward normal More dense  Less dense = away from normal * Change in speed* n1 n2 θ2 refracted ray

Note: This is why you see your reflection when you look out a window

Answer: Choice 1

Refraction (Special Cases) Special cases in which no bending occurs… Two mediums with the same index of refraction. A ray entering another medium at an angle of 0° n1sinθ1 = n2sinθ2 1.47 sinθ1 = 1.47 sinθ2 θ1 = θ2 corn oil glycerol n1sinθ1 = n2sinθ2 1.0 sin 0° = 2.42 sinθ2 0 = 2.42 sinθ2 θ2 = 0° air diamond

air is faster (lower index) Example A ray of light with a frequency of 5.09 x 1014 hertz moves from air into flint glass. The angle with which the ray strikes the surface of the flint glass is 40° away from the normal. Which is the faster medium? Determine the angle of refraction. Draw the refracted ray. air is faster (lower index) n1sinθ1 = n2sinθ2 1.00 sin 40° = 1.66 sinθ2 θ2 = 23° air flint glass