Light & Reflection
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Light travels in straight lines called photons at a fixed speed of 299,792,458 meters per second in a vacuum. Reflection occurs when light hits a surface and bounces off, either regularly like a mirror or diffusely, scattering the light. A shadow is the dark area behind an object that blocks light from directly reaching a surface, forming a two-dimensional silhouette of the object.
Light & Reflection
- 2. How do light forms 1. Light is electromagnetic radiation that we can see. Light beams are made of tiny 'packets' called photons. They travel form the source in a line through space until they are obstructed by matter.
- 3. What is the speed of light The speed of light in a vacuum is defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the meter is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum.
- 4. Light In this picture they are showing the light travels in straight line
- 5. What is reflection Reflection of light is either secular (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 light
- 6. Reflection
- 7. What is shadow A shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or reverse projection of the object blocking the light. The sun causes many objects to have shadows and at certain times of the day, when the sun is at certain heights, the lengths of shadows change
- 8. How do shadow forms Shadows are formed when an object passes in front of a light. As the light rays now bounce off this object the ground/objects behind the first no longer receives the rays and appears darker then the surrounding area (it will never be completely black do to bounce/ambient light)
- 9. Shadow
Editor's Notes
- #7: This is reflection