Microwaves-
Microwaves are electromagnetic waves with a wavelength shorter than radio waves and are commonly used in commincation and radar systems.
They have wavelengths approximately in the range 1 mm to 30 cm with a corresponding frequency range of 1 - 300 GHz.
Shorter microwaves with wavelengths of about 0.1mm are used in cooking. Microwaves are absorbed by water, fats and sugars in the food, whcih causes the food molecules to vibrate and heat up. Because the heating happens in the inside of the food, rather than in the surrounding air, the food cooks quickly but sometimes unevenly.
Specifically, a microwave oven uses a magnetron microwave generator to produce microwaves at a frequency of approximately 2.4 GHz for cooking food.
Glass, paper and many plastics don't absorb microwaves whilst metal reflects microwaves.
Another important application of microwaves is radar. The word "radar" was originally an acronym for RAdio Detection And Ranging. Today, its usage has become so common that it is now a word itself. Before World War II, British radio engineers found that short-wavelength radio waves could be rebounded off of distant objects like ships and aircraft, and the returning signal could be detected with highly sensitive directional antennas so the locations of those objects could be pin pointed.
They have wavelengths approximately in the range 1 mm to 30 cm with a corresponding frequency range of 1 - 300 GHz.
Shorter microwaves with wavelengths of about 0.1mm are used in cooking. Microwaves are absorbed by water, fats and sugars in the food, whcih causes the food molecules to vibrate and heat up. Because the heating happens in the inside of the food, rather than in the surrounding air, the food cooks quickly but sometimes unevenly.
Specifically, a microwave oven uses a magnetron microwave generator to produce microwaves at a frequency of approximately 2.4 GHz for cooking food.
Glass, paper and many plastics don't absorb microwaves whilst metal reflects microwaves.
Another important application of microwaves is radar. The word "radar" was originally an acronym for RAdio Detection And Ranging. Today, its usage has become so common that it is now a word itself. Before World War II, British radio engineers found that short-wavelength radio waves could be rebounded off of distant objects like ships and aircraft, and the returning signal could be detected with highly sensitive directional antennas so the locations of those objects could be pin pointed.
In today's society we use:
Microwave (Ovens) Percy Spenser was conducting radar experiments during World War II when he got close to a microwave-emitting tube and accidentally melted the chocolate bar in his pocket.He quickly understood the consequences of his actions, and the power of these microwaves, soon after he patented the first microwave heating device How does the microwave work? The food in your microwave sits in an electromagnetic field, attacked on all sides by high-frequency microwaves. Water molecules (along with some fats and sugars) absorb the microwaves, and then vibrate causing friction between molecules, thus heat. Inside the box, there is a microwave generator called a magnetron. When you start cooking, the magnetron takes electricity and converts it into high-powered, microwaves. The magnetron blasts these waves into the area where the food lies, waiting to be heated, through a channel known as a wave guide. The food sits on the plate, spinning slowly, round so the microwave can supossedly cook the food evenly. What does the Microwave do that other appliances can't do? The microwave not only heats up food quickly but it also is compact and energy efficent. Microwave ovens all use a timer in their standard operating mode; when the timer runs out, the oven turns itself off. They heat food without getting hot themselves. Hazards when using a microwave. Whilst only the water molecules ( and sugar or fats) may only be heated it can cause serious burns. An example of this is a jam-filled donut—the jam centre may exceed the boiling point of water while the donut itself is only warm. Hence, burning the interior of your mouth. Furthermore, severe scalding has also occurred when babies have been given milk heated in a microwave oven; whilst the plastic may be warm the contents are burning hot. |
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