ASSEMBLING OF MICROWAVE OVEN
ABSTRACT
However, certain of their properties render them ideal for cooking, by far the most common use of microwave energy.
Microwaves can pass through plastic, glass, and paper materials; metal surfaces reflect them, and foods (especially liquids) absorb them. A meal placed in a conventional oven is heated from the outside in, as it slowly absorbs the
surrounding air that the oven has warmed. Microwaves, on the other hand, heat food much more quickly because they penetrate all layers simultaneously. Inside a piece of food or a container filled with liquid, the microwaves agitate molecules, thereby heating the substance.
CHAPTER ONE
1.0 INTRODUCTION
Microwaves are actually a segment of the electromagnetic wave spectrum, which comprises forms of energy that move through space, generated by the interaction of electric and magnetic fields. The spectrum is commonly broken into subgroups determined by the different wavelengths (or frequencies) and emission, transmission, and absorption behaviors of various types of waves. From longest to shortest wavelengths, the spectrum includes electric and radio waves, microwaves, infrared (heat) radiation, visible light, ultraviolet radiation, X-rays, gamma rays, and electromagnetic cosmic rays. Microwaves have frequencies between approximately .11 and 1.2 inches (0.3 and 30 centimeters)
The term “microwaves” seems to have first appeared in writing in a 1932 paper by Nello Carrara in the first issue ofAlta Frequenza. The Italian word is microonde. The term gained acceptance during the second world war to describe wavelengths less than about 30 cm. These waves were much shorter than those normally used for communications (at that time), but were being used in RADAR.
A 30 centimeter wavelength is equivalent to 1 GHz (to convert from frequency to wavelength, just divide the speed of light 300,000,000 meters per second by the frequency in cycles per second to get meters of wavelength).
ASSEMBLING OF MICROWAVE OVEN