Some people have a lighter complexion and the others have a darker complexion.
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| Lighter Complexion |
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| Darker Complexion |
- The sun is so strong, I need to protect myself.
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| Sun Glasses |
- I have to wear sunglasses, I have learnt at school that she sunglasses’ lenses cause the reflection and refraction of light.
Reflection of light is either specular (mirror-like) or diffuse (retaining the energy, but losing the image) depending on the nature of the interface. Furthermore, if the interface is between a dielectric and a conductor, the phase of the reflected wave is retained, otherwise if the interface is between two dielectrics, the phase may be retained or inverted, depending on the indices of refraction.
Laws of reflection
If the reflecting surface is very smooth, the reflection of light that occurs is called specular or regular reflection. The laws of reflection are as follows:
1.The incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane.
2.The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal.
Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at any angle other than 90° or 0°. Refraction of light is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is described by Snell’s law, which states that the angle of incidence θ1 is related to the angle of refraction θ2 by
Experiment:
http://www.youtube.com/watch?v=AzBZK9mTAKs
