The uses of microwave are somewhat similar to that of radio waves. They are used in communications, radio astronomy, remote sensing, radar and of course, owing to their heating application, they are used in cooking as well. The way radio waves and microwaves are received and transmitted vary. The frequency of microwaves ranges from 300 MHz to 300 GHz while the wavelength ranges from 1 mm to around 100 cm.
Why mobile phones use microwaves? Because microwaves can even be generated with the help of small antennas, so the mobile phones need not be of large size.
Something which is not very well known is the use of microwave in getting the first clues to the occurrence of the Big Bang. In the 1960’s, two scientists, who happened to be working with special low noise antennae, noticed something very strange. They were picking up noise from all directions and they noticed something even stranger. The noise from all directions did not vary in its intensity. Arno Penzias and Robert Wilson, the two scientists, figured that if it were coming from anywhere on earth, then the direction would be quite specific… but it wasn’t!
They realized that they had discovered cosmic microwave background radiation by mistake! This microwave radiation fills the entire radiation and was our first clue to the occurrence of the Big Bang!
There is a wide belief that since microwaves emit radiations, they are not good for health. But microwaves fall under the low frequencies of the electromagnetic spectrum. They also have low energies. Therefore they do not have enough energy to chemically change substances through ionization. Radiation here means having energy and not radioactivity. And there are some studies which suggest carcinogenic effects (these are not the same as previously mentioned high energy emitting exposure).
Stay tuned with byju’s to learn more about electromagnetic spectrum, gamma rays and much more.
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