sin i sin r n Using Snell’s Law sin 𝑖 sin 𝑟 =𝑛 x Example 1: Light passes from air to perspex (n=1.49), with an angle of incidence of 52°. What is the angle of refraction? Step 1 – rearrange the equation to give r. sin 𝑖 𝑛 = sin 𝑟 Step 2 – plug the numbers in. sin 52° 1.49 = sin 𝑟 Step 3 – calculate sin i. 0.78 1.49 = sin 𝑟 Step 4 – calculate the fraction. 0.52 = sin r Step 5 – eliminate the sine. 0.52 x sin-1 = (sin r) x sin-1 052 x sin-1 = r Step 6 – last calcuation! 31.33 = r Step 7 – and breathe! Snell’s Law sin 𝑖 sin 𝑟 =𝑛 sin i sin r n x sin i sin r n x Index of Refraction for some common substances: Water: 1.33 Diamond 2.42 Flint Glass 1.67 Cubic Zirconia 2.20 Pyrex 1.47 Plastic 1.5 Polycarbonate 1.58 A light ray approaches a crown glass block at 49° and refracts at 28.1°. What is the refractive index of the crown glass block? If n=1.3 and i=23°, what is the angle of refraction? If n=1.1 and r=4°, what is the angle of incidence? If i=34° and n=1.4, what is r? If r=20.3° and i=50, what is the refractive index? Compare your answer to the table above; what is the substance that refracted the light? Write a question (and answer) that asks for i. Write another two questions for n and r.

sin i sin r n Using Snell’s Law sin 𝑖 sin 𝑟 =𝑛 x Example 1: Light passes from air to perspex (n=1.49), with an angle of incidence of 52°. What is the angle of refraction? Step 1 – rearrange the equation to give r. sin 𝑖 𝑛 = sin 𝑟 Step 2 – plug the numbers in. sin 52° 1.49 = sin 𝑟 Step 3 – calculate sin i. 0.78 1.49 = sin 𝑟 Step 4 – calculate the fraction. 0.52 = sin r Step 5 – eliminate the sine. 0.52 x sin-1 = (sin r) x sin-1 052 x sin-1 = r Step 6 – last calcuation! 31.33 = r Step 7 – and breathe! Snell’s Law sin 𝑖 sin 𝑟 =𝑛 sin i sin r n x sin i sin r n x Index of Refraction for some common substances: Water: 1.33 Diamond 2.42 Flint Glass 1.67 Cubic Zirconia 2.20 Pyrex 1.47 Plastic 1.5 Polycarbonate 1.58 A light ray approaches a crown glass block at 49° and refracts at 28.1°. What is the refractive index of the crown glass block? 1.6 If n=1.3 and i=23°, what is the angle of refraction? 17.4° If n=1.1 and r=4°, what is the angle of incidence? 3.78° If i=34° and n=1.4, what is r? 23.54° If r= 20.3° and i=50°, what is the refractive index? Compare your answer to the table above; what is the substance that refracted the light? N = 2.20 = Cubic Zirconia Write a question (and answer) that asks for i. Write another two questions for n and r.