Download presentation
Presentation is loading. Please wait.
1
Absorption, reflection and refraction
2
Light travels VERY FAST – about 300,000 kilometers per second or 186,000 miles per second.
At this speed light could travel the equivalent of 8 times around the world in one second!
5
Absorption When light is absorbed by a material, the frequency of the light wave is very close to the vibration frequency of the electrons in the receiving material. The receiving material has a tendency to hold onto its electrons very tightly. When the light hits the receiving material, its electrons absorb the energy of the entering light and begin to speed up and collide with other atoms. As result, they attempt to release as much energy as possibly by giving off heat. When we are hit by the powerful energy of the sun, our bodies absorb the energy but try to cool us down by giving o heat.
6
Transmitted light waves are similar to reflected light waves, except they occur in transparent material instead of opaque material. In the case of transmitted waves, the frequency of the entering light does not match the natural vibrating frequency of the receiving material. The electrons in the material's atoms do not capture the energy of the incoming light and the wave passes through the material unchanged. Light waves are reemitted on the opposite side at the same angle at which they entered.
7
When light is reflected, none of the entering light matches the natural frequency of the receiving material, which is considered opaque. The electrons in the receiving material are held very loosely. In this case, when electrons in the receiving material are energized by the incoming light, they vibrate for only a short period of time and then light waves are sent back out of the object at the same frequency as the incoming wave. According to the law of reflectance, the light is reflected back at an angle equal to that of the entering wave.
9
Refracted light waves are similar to transmitted waves as light exits the material on the opposite side as it enters. The difference is that light refracts when the entering wave is of the same frequency as the natural vibrating frequency of the material. The electrons of the receiving material capture the energy of the entering light and begin vibrating. The vibrations are passed on to neighboring atoms until the energy escapes by means of a wave exiting at the same frequency. The deep penetration of the light wave takes time and the portion of the wave inside the material slows down. This has the effect of bending the light and the angle of bending or "angle of refraction" depends upon the material's properties. Placing a pencil in a glass of water demonstrates the bending property because the index of refraction of water is different than air.
10
Absorption
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.