Chapter 11: LIGHT WAVES

Chapter 11: LIGHT WAVESBy: Chong Yeon Park 10DDLight wavesThere are many sources of light such as Sun. Objects like these can emit their own light are called luminous objects.We see non luminous objects due to the light that they reflect.We see the object when the emitted light enters our eyes. Are transverse waves, can be reflected, refracted and diffractedWe are capable to see objects due to the fact that we emit or reflect light.

An image is reflected as a ray of light strikes the mirrorAs this occurs the angle of incidence is equal to the angle of reflection

Reflection Refraction is the change in direction of a wave/ray passing from one medium (material like glass or water) to another caused by its change within speed. Rays of light can travel through many transparent materials including objects such as vacuum, air, water and glass. In a vacuum and in air, light can possibly travel at a speed of 300,000,000m/s. The speed of light in water is approximately 200,000,000m/s. As a ray of light travels through a glass block, it slows down and is refracted towards the normal. As the ray leaves it speeds up and refracts away from the normal. Refraction

Refractive IndexYou can experiment refraction through an observation in glass whilst utilizing a rectangular glass block. By tracing the rays of light on a sheet, you can measure the angles of incidence and refraction Equation of the angles of incidence and refraction and the refractive index:

Total Internal ReflectionWhen a ray passes from an optically more dense medium in an optically less dense medium e.g. glass into airMajority of the light is refracted away from the normal but there is a small amount that is reflected from the boundary. As the angle of incidence increases in the more dense medium, the angle of refraction increases until, at a special angle called the critical angle, the angle of refraction is 90

Critical AngleIs the angle of incidence above which the total internal reflection occurs. Equation of Critical Angle: