Senin, 17 Desember 2012

how rainbows are formed?

Have you ever seen the rainbow? Beautiful is not it?
Have you ever noticed that the rainbow is a natural phenomenon that occurs with physical processes that are very interesting to learn. Here, then, will be described how paoses the rainbow. 
Rainbow is an arc spectrum which occurred due to refraction of sunlight by drops of water. The rainbow is an optical and meteorological phenomenon in the form of colorful light parallel to each other in the sky or other medium. In the sky, a rainbow appears as an arc light at the end leads to a time horizon of light rain. Rainbow can also be seen around a raging waterfall.
This occurs when the air is very hot but rain drizzle. We can see this phenomenon clearly, if we stand back to the sun. Rainbow can also be formed due to foggy or dewy air.
In physics, a rainbow can be explained as a natural refraction event. Refraction is the process diuraikannya a specific color to some other color (also called spectral colors), with a medium / medium well specified.
In the rainbow, color berurainya process occurs when white sunlight breaks down into a spectrum of colors with medium rain. The spectrum of colors that occur consist of red, orange, yellow, green, blue, indigo, and violet.
Rainbow phenomenon can also occur around the falls. Splash water around the falls as a medium to describe the color of the sunlight that shines.
Occurrence Process Rainbow
The sunlight is polychromatic light (made up of many colors). The white color of sunlight is actually a combination of various wavelengths of light with different. The human eye can perceive at least seven colors contained in sunlight, which will look at the rainbow: red, orange, yellow, green, blue, indigo, and violet.
The wavelength of light is forming ribbons parallel lines, each color shades of the color next to it. The tape is called a spectrum. In the spectrum, the red line has always been on one side and blue and purple on the other, and this is determined by the difference in wavelength.Rainbow arc spectrum is nothing that is happening because of the refraction of sunlight by drops of water. When sunlight through water droplets, such as when he refracted through a glass prism. So in a trickle of water, we've got different colors extending from one side to the other water droplets. Some of the colored light is then reflected from the far side of the water droplets, again and again out of the water droplets.
The light came back out of the water droplets in different directions, depending on the wavelength. Different wavelengths, will bring the colors of the rainbow are arranged with red top and purple on the bottom of the rainbow.
Rainbow can only be seen when the rain along with the sun shining, but from the opposite side to the viewer. The position of the observer must be between the sun and the water drops with the sun dibekalang person. The sun, the eye of the observer and the center of the arc rainbow shall be in a straight line.

 The cause of the refraction of light
 Refraction of light occurs when light passes from one medium to another with the propagation of different optical densities, changing speed and changing direction if not incident perpendicular to the surface. Refraction is the deviation in the direction of light propagation is described by Snell's law. Law and refraction in homogeneous media, is a consequence of Fermat's principle, which states that light travels between two points along the optical path requires a little more time.

In addition, the speed of light in a medium other than penetration associated with vacuum wavelength and, when a beam of white light passes from one medium to another, each color having a little deviation. This phenomenon is known as the scattering of light. For example, to achieve a solid medium, the wave loses speed on shorter term (eg, when white light passes through a prism). Shorter wavelengths are scattered up to 4 times during it which is why the sky looks blue because the color range for the index of refraction larger and more spread out.

In the law of refraction is Huygens concluded all control over the entire wave motion:

   1.  Rays incident, reflected and refracted are in the same plane.
   2. Angles of incidence and reflection are the same, which means they each incident and reflected beams perpendicular (called Normal) for the boundary drawn at the point of incidence.

picture a. shows water waves propagate from one medium into another medium to after passing the boundary between the two media, the wave is experiencing deflection. In the event of any change and the direction of wave propagation λ2 wavelengths shorter than λ1.
Figure (b) shows the change in wave speed. The wave propagates from a medium that has a refractive index n1 to another medium of refractive index n2
(a) The change in wavelength, λ2 shorter than λ1.
    b) Changes in wave velocity, v2 is smaller than v1.
The second image is derived from the refraction of the wave equation as follows:
sin i / sin r = v1/v2 =
(fλ1) / (fλ2) = λ1/λ2 
From one medium to another medium, the frequency of the wave remains. So that changes the speed and wavelength

2 komentar:

Mulinda Dewi Lestari mengatakan...

is the rainbow having kalor?

melvika anggraini mengatakan...

why we use prism glass to prooved the rainbow process in experiment?