external image frequency.gifRadio wavesexternal image antenna_and_radio_waves.png


What are they?
Radio waves have the longest wavelengths in the electromagnetic spectrum.They range from the length of a football to larger than our planet.You can tune a radio to a specific wavelength—or frequency—and listen to your favorite music. The radio "receives" these electromagnetic radio waves and converts them to mechanical vibrations in the speaker to create the sound waves you can hear.

Are they dangerous?
they are not dangerous at all.However, like all electromagnetic radiation, radio waves are made up of energy. And that energy can be absorbed. Radio waves with a frequency of a few centimeters can easily be absorbed by your body, and there be turned into heat energy. As such, a significantly powerful radio transmitteremitting in the right frequency would be able to heat your body. And if your body can heat, then it can boil. And then you will die.

Where do they come from?
Radio waves are energy waves that are generated by a transmitter. Radio waves are also commonly referred to as electromagnetic radiation and the typical shape of the wave produced by a transmitter is that of a sine wave.

How do we detect them?
Radio waves are detected by the use of radio telescopes. Electromagnetic waves are detected by means of their wavelength and frequency. It also uses amplitude modulation and frequency modulation for detection.

What can they be used for?
Radio waves can be described as electromagnetic waves that have a frequency range between 3 kHz and 300 GHz. They are non-ionising radiation, and have the longest wavelength. These waves can be used in radio, radar and broadcast communication, and other navigation systems.

Anything else interesting?
Radio waves bounce round the earth.
They travel at the same time as light.
These waves are the fastest possible way to move the information from one place to another place.

Mobile phones and how they work and communicate

When you are on the phone to a relative or friend in a completely different place your phone converts your voice into an electrical signal, which is then transmitted as radio waves and converted back into sound by your friend’s phone. A basic mobile phone is therefore little more than a combined radio transmitter and a radio receiver, quite similar to a walkie-talkie or CB radio.In order to remain portable, mobile phones need to have relatively compact antennas and use a small amount of power. This means that mobile phones can send a signal over only a very short range, just like a walkie-talkie.

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In the table below, fill the cells with very brief notes. Use the other pages to gather the information from, and you may want to go outside of this wiki if you really can't find the information here (though I'd be surprised!).



Gamma
X-rays
UV
visible
IR
microwaves
radio
How are they generated?
Stars, super novas, black holes and pulsars. They are also created on earth
by natural radioactive decay,by nuclear explosions and by lightning in thunderstorms.
They are classically produced by gamma decay.
They are generated by machines and stars.





How are they detected?
Gamma-ray detectors typically contain densely packed crystal blocks. As gamma
rays pass through, they collide with electrons in the crystal.We detect gamma rays by using
telescopes, but they don't look like normal telescopes.They observe gamma
rays indirectly, by monitoring flashes of visible light. Gamma rays
are a form of radiation.
In hospitals the pictures were captured using image
receptors such as thin films and photographic plates.
Now they use computer technology
to generate the images produced by X-Rays.
Astronomers also use X-Rays, as these
are absorbed by the earth's atmosphere they use
balloonsand satellites at very high altitudes.X-Rays
can be indirectly sensed by humans but they
cannot be seen by any human or animal eye.





How might they be dangerous?
They are extremely harmful to living creatures, which is why they're used to destroy
cancerous cells.They cause biological harm as their rays are ironing radiation.
X- rays can damage cells and cause cause cell
mutation which can cause cancer or cell death. It
can cause these illnesses as it produces radiation
as do lots of high frequency waves, this causes
cells to behave differently and can have severe
effects.





What are the main or most significant uses?
They are used to kll cancer cells.Gamma-induced molecular changes can also be used to alter
the properties of semi-precious stones. Gamma rays can be used to detect for element of
different planets.
To scan for bone breakages or in dentists. They are also used at airports to check the luggage.





Good work. The section radio waves deserves the merit.

The table is incomplete - but you'll be able to see the orgers!

Well done!

B+ merit
ome page>