There is a simple relationship between the wavelength and frequency of a particular color of light and the speed of light. This is actually the speed that all electromagnetic radiation travels not just visible light. For example, it always travels at a speed of approximately 3 x 108 meters per second in a vacuum. Light has a constant speed through a given substance. Cycles per second and Hertz mean exactly the same thing. It is measured in what used to be called “cycles per second”, but is now called Hertz, Hz. If you counted the number of crests passing a particular point per second, you have the frequency of the light. You have to picture these wave crests as moving from left to right. It could equally well be the distance between two troughs or any other two identical positions on the wave. If you draw a beam of light in the form of a wave, without worrying too much about what exactly is causing the wave, the distance between two crests is called the wavelength of the light. The energy in light travels because of local fluctuating changes in electrical and magnetic fields hence “electromagnetic” radiation. With water waves it is fairly easy to draw diagrams to show this happening with real molecules.
The energy is transferred by relatively small local movements in the environment. As they move up to the top of the circle, the wave builds to a crest as they move down again, you get a trough. Depending on the depth of the water, waves follow a roughly circular path from the point of origin.
With waves on water, the energy is transferred by the bulk movement of water molecules however, a particular water molecule doesn’t travel all the way across the Atlantic, or even all the way across a pond. Any wave is essentially just a way of shifting energy from one place to another, whether the fairly obvious transfer of energy in waves on the sea or in the much more difficult to imagine waves in light. To answer this question, we need to know some important characteristics of light in general.
0 kommentar(er)
