Refraction of light | Physics | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! https://www.khanacademy.org/science/h... Want to explore more? Check out the full electromagnetic radiation playlist here:    • Electromagnetic radiation | Physics | Khan...   Light refracts—it bends—when it passes from one medium into another at an angle. Refraction occurs because the phase velocity of light is different in different media. For example, light slows down when it passes from air into glass. This happens because the incoming electromagnetic wave causes electrons in the medium to oscillate, which produces a secondary electromagnetic wave. The resulting wave, which is a superposition of the incoming wave and the secondary wave, has a different phase velocity than c. Sections: 00:00 - What is refraction? 01:19 - Understanding wavefronts 03:35 - Why does light refract? 05:56 - What does bending of light depend on? 07:20 - Why does light change speed? 08:30 - Constructive and destructive interference 10:54 - Interference causes phase kick back 12:05 - Modeling change in light speed as a continuous phase kick back 13:35 - What causes dispersion? ------------------ Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help! Donate here: https://www.khanacademy.org/donate?ut... Volunteer here: https://www.khanacademy.org/contribut...