Light.ppt

1. L I G H T CREATED BY : IZZATUN NUR ALIFAH 09330191

2. LIGHT Light is an electromagnetic wave, namely the wave the vibration of which is electric field and magnetic field. Light is included into transversal wave. Light can spread without medium, so light can spread in vacuum.

3. While several properties of light among other are : Spreading according to straight line Has energy Can be seen Radiated in the form of radiation Has spreading direction perpendicular to vibration direction Can experience reflection, refraction, interference, diffraction, and polarization

4. Bodies that can spread light is called light source. While bodies that cannot spread light theirself is called dark body.

5. Sorting light sources Natural vs. Man-made (artificial)

6. Are these light sources? moon water mirror These items are not light sources, instead they are reflecting light from other sources.

7. light source Light rays travel in straight lines from the light source. When it hits an opaque object, some light is absorbed and the rest reflects off. If the object is transparent , light rays pass through it easily. If the object is translucent , some light can pass through, but the rest of the light will be reflected.

8. Light Reflection Angle of incidence Angle of reflection The ‘angle of reflection’ is always equal to the ‘angel of incidence ’. r = i on off If a light hits a body surface commonly will be reflected.

9. Law of Reflection Incident angle, normal line and reflected ray lie on one flat plane Incidence angle is equal to reflected angle ( i =r)

10. How does light form shadows? Light rays travel in straight lines, radiating out from the light source. If rays are blocked by an opaque object a shadow forms where the light cannot reach. If the light source is moved closer to the object, more light is blocked and a larger shadow is formed. light source light source

11. Specular Reflection Reflection ray Incidence ray happens if the stream of light falls on the body that its surface is smooth and shiny, so direction of the light reflection goes to certain direction.

12. The diffuse reflection Incidence ray Reflection ray Happens if the stream of light falls on the body which its surface is rough (not flat), so the stream of paralles rays which fall on the body will be reflected to every direction.

13. Thanks for Your Attention