what is a radio wave physically ?
471190
Electromagnetic radiation in the 1 to 1000 m wavelength range.
1060331
Electromagnetic waves. When a wave reaches a surface seperating two media refraction occurs.
270577
A pulse of energy - electromagnetic radiation. So anything from radio waves to gamma rays counts as electromagnetic radiation. A pulse of this energy is usually associated with nuclear weapons due to the high intensity of radiation emitted by a thermonuclear reaction.
1006427
RADAR is an acronym that stands for RAdio Detection And Ranging.  It works by emitting a very short pulse of radio frequency energy.  This energy travels out from the Radar antenna until it strikes the surface of a radiowave refective object.  A portion of this energy is returned to the antenna, where it is detected.  Since radio waves move at the speed of light (~186,000 miles per second), this means that it travels one mile every 6.7 microseconds (6.7 millionth of a second).  This might seem like a very fast time, but is still easily measureable.  So if the pulses refection returns in 13.4 microseconds, that means the object is one mile away. (6.7 out + 6.7 back).  The radar equipment is designed to know what direction the antenna is pointed when it send out its pulse, so it can then show on its display exactly where the target is located in both direction (azimuth) and distance (range).\n  As for how it effects the body,  Radar energy is a form of microwave energy, same as the stuff in your microwave oven.  Microwave energy has the effect of heating different types of molecules, such as water, sugar and fats.  This heating effect can damage the body just as if you were inside a microwave oven.  However, as said before, the actual energy pulse is very short.  Remember, after the pulse is produced, you have to wait for the pulse to return before you can send out the next one.  So most radars have an average power (power over time) of not much more than a 60W lightbulb.  Also remember that, except for a few special types, radar antennas are constantly spinning around, so that the amount of energy that passes by any one place is very small.  You can be as close as 5 feet away from most navigation radars without any fear of injury.  (just don't stay there for too long).
922623
v = f * lambda\n(where v is velocity, f is frequency and lambda is wavelength)\n\n:. lambda = v / f\nv = 3 * 10^8 m/s (speed of an electromagnetic wave)\nf = 88 MHz = 88000000 Hz\n\n:. lambda = 3*10^8 / 88000000\n                = 3.41 m\n\nie. the length of a typical radio wave is 3.41 m
856950
IR ray is an electromagnetic wave, like visible light, X-ray, gamma ray and UV ray(even radio waves). the energy of IR wave is lower than visible, UV, X-ray and gamma. when one of the high energy electromagnetic waves hit a molecular, they will brake it to smaller parts( if they have enough energy) but IR doesn't have enough energy, so all it can do is to make the molecules move faster. the movement average of molecules is what we call heat, so when IR hits a material, it'll rise the average molecular movement in it and we say that the material became hotter.
461697
Depends on what sort of electromagnetic waves you mean...\n\nMicrowaves, X-rays etc\n\nStudies are being conducted all the time to test this, but most electromagnetic radiation found in the home has to have been judged safe by govermental bodies, otherwise it wouldn't be sold!!\n\nJust be wary of getting too close to microwaves if you have a heart pacemaker.
126863
The RF waves emanating from an antenna are generated by the movement of electrical charges in the antenna. Electromagnetic waves can be characterized by a wavelength and a frequency. The wavelength is the distance covered by one complete cycle of the electromagnetic wave, while the frequency is the number of electromagnetic waves passing a given point in one second. The frequency of an RF signal is usually expressed in terms of a unit called the "hertz" (abbreviated "Hz"). One Hz equals one cycle per second. One megahertz ("MHz") equals one million cycles per second.
932826
The radio uses a transducer called an aerial to convert the radiowaves to current in a conductor, after low noise amplification and filtering to reject most of the other radiowaves that the transducer has converted, the short-term changes in the current are interpreted as a wanted modulation of the radiowave.
940858
The radio waves currently used for telecommunication or broadcasting are electromagnetic waves (non-ionizing radiation) which do not have enough energy to ionize atoms from materials. Although some of the electromagnetic waves, such as ionizing radiation including X-ray or gamma-ray, have high frequencies and strong energy that ionize atoms, they are very different from the radio waves we are dealing with; that is non-ionizing radiation.
362672
Radiowaves, look it up.\nAnd you definately got the category wrong.
762445
More complex radar systems, like those used at airports, allow radio waves to be imaged on a computer screen. They send out a beam of radio waves (like a flashlight sends out light), collect the waves that reflect of off distant objects, and reconstruct the wave pattern into an image (like the eye does with light). The result is displayed for the operator to see.
626652
the lowest frequency, like low-band radio has a wavelength of about 2-300ft, but theoretically if you could produce EM waves at frequencies much lower then that, you could get wavelenghts of even light years in length, but that's not very practical to do, i doubt if its even possible.
1095930
first of all lets define radiation.\nradiation is the emission of waves or wave travel.\na wave comprises of wave lenths\n1 wave lenth is 1 crest and 1 trough\nwhat are the different types of waves\nthere are two main types\nfirst is the non-ionizing radiation or harmless\nand second is the ionizing radiation or harmful\nplease refer to an electromagnetic spectrum in where it is indicated in detail\nfrom non-ionizing:\nlong waves, radio waves,microwaves, infra-red, visible/white light\n to ionizing:\nUV, x-rays and gamma rays.\nThree main types of ionizing radiation\n1. alpha rays - highly ionizing weakly penetrating\n2. beta rays - med ionizing med penetrating\n3. gamma rays/x-rays - highly penetrating weakly ionizing\n\nso radiation from a blast could be light, and heat but if you use a nuclear bomb there will be ionizing radiation that will affect people and living things.\n\nthe difference between a bomb and a nuclear bomb or dirty bomb is that inside a bomb there are/is radioactive sources like Po, U, Fe and other radioactive sources.\n\nhow does it harm us. you cannot feel ionizing radiation. no human senses can detect them. only specialized equipment do like a geiger counter. ionizing radiation can alter DNA. so if you are affected by large dose, some of your cells will die and alter your DNA.\n\nprotect..?\n\nby using the Time Distance and Shielding concept\nless time you are expose less effect on your body\nradiation reduces its effect by 1/4 every 1 meter\nyou can shield yourself to radiation by knowing what radiatioactive source you are being exposed.\nalpha ray can be blocked by our own dead layer of the skin or paper\nbeta could be blocked by much denser material like book, water, aluminum, glass\ngamma could be blocked by a thick concrete or lead\n\nPM is you have more question
738961
Sorry, you're going to have to be a bit more specific than that. Electromagnetics is a rather broad subject.\n\n~X~
92774
Radiowaves do hardly anything. No harm\nMicrowaves and infrared heat your body\nVisible light makes you visible and psychological healthy.\nUltraviolet can make you blind.\nX- and gamma rays go throught your body and make damage.\nFrom up to down, the more dangerous.\n\nFor all EMW: the more intensity, the more dangerous.\nthe more time of radiation, the more dangerous.\nThe closer to the source of the radiation, the more dangerous.
141854
Ok, so some people should not be posting answers here.\n\nRadio waves do not pass through all objects.  It depends on two things, the dielectric constant of the object and thus the frequency of the radio wave.\n\nFor example, if you have a conductor (copper, or aluminum or iron) it will reflect the radio waves.  The waves will not pass through the object.\n\nFor most objects that are not conductors, when you pass from free space (air) to a solid like concrete, a portion of the radio wave will reflect off the surface (a small portion), some of the energy of the wave will be absorbed by the object, but the rest of the wave will pass through. \n\nDepending on the thickness of the material and the frequency of the signal, and the dielectric constant of the material, sometimes radio waves will not pass through the object.  As the signal travels through the material, it will continuously lose active power (heat) and reactive power (stored energy like in a capacitor).\n\nIf you were to compare the signal strength before it hits the wall, and the signal strength after it leaves the other side of the wall, some energy would have been lost.