Refraction - Snell's Law & Extensions PDF

Refraction – Snell’s Law & Extensions P4 Lesson Learning Goals I will be able to complete calculations using Snell’s Law I will be able to accurately determine the direction of the refracted ray by measuring angles Ref...

Refraction – Snell’s Law & Extensions P4 Lesson Learning Goals I will be able to complete calculations using Snell’s Law I will be able to accurately determine the direction of the refracted ray by measuring angles Refraction – Snell’s Law (Video) Snell’s Law 𝑛1 = index of refraction of medium 1 (unitless) θ1 = angle of incidence (degrees) 𝑛2 = index of refraction of medium 2 (unitless) θ2 = angle of refraction (degrees) ❖ This formula allows you to use index of refraction values to calculate the new angle (θ2) the ray will take as it strikes the interface of the two media Examples in table pokup n o 1. A laser beam is passed from the water through a block of cubic zirconia. The angle of incidence is 50° and the angle of refraction is 27°. Calculate the index of refraction of cubic zirconia. n 1.33 Misino nasino rinsing FIs sink 02 270 2.2441 2.24 1 Refraction – Snell’s Law & Extensions P4 Lesson n n O Or 2. A light ray traveling in air strikes water at 60° from the normal. What is the angle of refraction? misino nasino n 1.00 n 1.33 sing misino m 0 60 2 1.00sinto 02 0 sin 0.65114692 40.6 i theangleofrefractionis40.6 n n 3. A light ray passes from water (n = 1.33) into flint glass (n = 1.61). The light refracts 47° from the interface between the two media. What was the angle of incidence? nonsino É sino nasino 1.61in43 02 745 47.43 0 sin 0.8255769 55.6 Snell’s Law Extensions (Video) i theangleofincidenceis 55.6 When light moves from high n → low n, it bends away from the normal ○ If this angle continues to increase, it can cause the the light to refract parallel to the surface ○ At this point, no light actually enters the new medium Critical Angles & Total Internal Reflection (Video) ❖ Critical Angle (θC): the angle of ❖ Total Internal Reflection: The angle of refraction (θ2) is incidence (θ1) that causes the angle greater than or equal to 90° (light is completely of refraction (θ2) to equal 90° reflected back into the starting medium) 2 Refraction – Snell’s Law & Extensions P4 Lesson Examples 1. A light ray is passing from glass (n = 1.45) to air. What is the critical angle? ii a is sina.si 02 900 glis's n 1.00 0 sin 9 Ho sin s i thecriticalangle is 43.6 43.6 2. The critical angle for an unknown substance (in air) is 55°. What is its index of refraction? 5 ss 9 i sinai tame ns.t.oo sit I S In 3. a) A light ray is passing from plastic (n = 1.5) to water (1.33). What is the critical angle? no _nasino I 0 sin 59 mass 1 I i thecriticalangleis62.5 b) If the angle of incidence is 75°, what is the angle of refraction? angle of insidences critical angle total internal reflation 75 Misino nasino I se 02 sin msn.IQ no refraction Or sin s 1.59 Nz 1.33 sin Y ERROR 3 Refraction – Snell’s Law & Extensions P4 Homework Practice Questions Short Answer 1. Draw the normal, measure the angle of incidence, calculate the angle of refraction, then draw the actual refracted ray. nising nasino sina.i.ss.no sino 1.2 22 if ua a) a a.es b) 2. n Light travels from water n a into a ruby at an angle of 50°. 3. The refractive index of the lens in a human eye is 1.41. If The angle of refraction is 35°. What is the index of a ray of light goes from the air into the lens at an angle of refraction for ruby? a 55°, what is the angle of refraction? v 9 350 1.776 809 refractionofrubyis1.78 indexof i the i theangle ofrefraction is 35.5 4. Jade has an index of refraction of 1.61 and light 5. A student is given an unknown clear material. She approaches the gem at an angle of 80° shines a laser at its surface at an angle of 25°. The fromair angle of the refracted ray is 16.7°. What material is it? What is the angle of refraction? misino nasino ii misino nasino Q www.msn i I I i sina.sins.is n itheangleofrefractionis37.70 6. The angle of incidence from air is 60° and the angle of 7. What is the critical angle for diamond (into air)? *4* refraction in the material is 50°. Use this angle to explain why diamonds sparkle. Calculate the index of refraction of the material. rising rising i sina.mn 1.13 ithecriticalanglefor imndis24.4 indexofrefractionis1.13 i the 4