At 12:04 PM 6/20/02, Reggie Bautista wrote: >Dan wrote: >>O.K. fair enough. I was definately thinking about the link you gave below. >>I'll stand corrected to in the range of 3-5 million times larger than cell >>phones. > >Sounds reasonable to me that in that range, it would be hard to find >problems with cell phones that don't occur with radio towers. Could >proximity to the phone vs. lack of proximity to the tower make a difference?
The strength of an EM waves falls off as the square of the distance from the source, the so-called "inverse-square" law. >I guess part of my problem in understanding all of this is that, despite >the fact that I worked in radio for just over 5 years, I really don't have >a good understanding of what exactly a "radio wave" is. In acoustic >terms, a soundwave is just a graph of moving areas of higher and lower >pressure; nothing actually moves from point a to point b. Are radio waves >in any way analogous to this, or are their particles that move from one >location to another like photons coming from the sun to earth? Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays are the traditional names given to different portions of the same continuous spectrum of electromagnetic radiation. Each type of EM radiation, like visible light, sometimes behaves like a wave and sometimes like a particle. As one moves along the spectrum in the order given, the wavelengths get shorter, the frequencies get higher, and the energy of individual photons increases. The names were assigned as different portions of the EM spectrum were identified by experimenters: only later did the overall pattern become clear. There is no clear dividing line between adjacent regions of the spectrum, any more than there is a clear dividing line between adjacent colors of visible light. In fact, as defined traditionally, some of the sections partially overlap: for example, the same energy photon may be called an X-ray if it is created in a process involving electrons in the innermost shells of a large atom but a gamma ray if it is emitted from within the nucleus. All types of electromagnetic radiation move through empty space at the same speed: 299,729,458 meters/second. Sound waves, OTOH, cannot move through a vacuum, but only propagate through a continuous medium such as air, water, or a solid. In general, the denser and more elastic the medium, the faster that sound waves move through it, e.g., sound moves several times faster through steel than air. OTOH, when electromagnetic radiation encounters a material medium transparent to that particular type of radiation, it slows down, with the amount of slowing being a function of the medium and the wavelength/frequency of the radiation. For example, visible light slows to about 3/4 the above speed in water, about 2/3 of the above speed in glass, and about 4/9 of the above speed in diamond. >Or am I even asking intelligent questions here? Yup. >Thanks in advance to anyone who can help me clear this all up in my head. Did this help? >I appreciate it. -- Ronn! :) Ronn Blankenship Instructor of Astronomy/Planetary Science University of Montevallo Montevallo, AL Disclaimer: Unless specifically stated otherwise, any opinions contained herein are the personal opinions of the author and do not represent the official position of the University of Montevallo.
