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Visual Representation of Microwaves

Answer: The microwave region extends from 1,000 to 300,000 MHz (or 30 cm to 1 mm wavelength). Although microwaves were first produced and studied in 1886 by Hertz, their practical application had to await the invention of suitable generators, such as the klystron and magnetron.L

Microwaves are the principal carriers of high-speed data transmissions between stations on Earth and also between ground-based stations and satellites and space probes. A system of synchronous satellites about 36,000 km above Earth is used for international broadband of all kinds of communications—e.g., television and telephone.

Microwave transmitters and receivers are parabolic dish antennas. They produce microwave beams whose spreading angle is proportional to the ratio of the wavelength of the constituent waves to the diameter of the dish. The beams can thus be directed like a searchlight. Radar beams consist of short pulses of microwaves. One can determine the distance of an airplane or ship by measuring the time it takes such a pulse to travel to the object and, after reflection, back to the radar dish antenna. Moreover, by making use of the change in frequency of the reflected wave pulse caused by the Doppler effect (see above Speed of electromagnetic radiation and the Doppler effect), one can measure the speed of objects. Microwave radar is therefore widely used for guiding airplanes and vessels and for detecting speeding motorists.

Understand how microwave ovens work and if they are harmful to humans

Learn about microwaves and how microwave ovens work.

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Microwaves play an increasingly wide role in heating and cooking food. They are absorbed by water and fat in foodstuffs (e.g., in the tissue of meats) and produce heat from the inside. In most cases, this reduces the cooking time a hundredfold. Such dry objects as glass and ceramics, on the other hand, are not heated in the process, and metal foils are not penetrated at all.