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ELECTRICAL PROPERTIES (Electrical Resistance and Ohm's Law (When a…
ELECTRICAL PROPERTIES
Electrical energy is used for heating purposes, in the production of steam, hot water and hot air.
Include the resistance, the conductance and the dielectric properties of food.
Electrostatic deals with the study of electrons at rest, whereas electricity currents are electrons in motion.
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Dielectric Properties
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Dielectric loss factor (ε”) = Ability of a material to dissipate microwave energy into heat It also measures microwave absorptivity.
Materials having a high loss factor, the rate of heat generated decreases rapidly and microwave energy does not penetrate deeply.
Power penetration depth (δp) = A parameter is necessary to indicate the distance that microwaves will penetrate into the material before it is reduced to a certain fraction of its initial value.
Frozen Food
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The dissipation or loss factor for solid ice has a very low value when compared to that of liquid water
Ice is essentially transparent to microwaves, just as glass is to light
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Microwave Heating
Determination of dielectric properties becomes significant to understand the heating profiles of foods in a microwave oven
Electromagnetic waves, cover a spectrum of frequencies ranging from 300 MHz to 30 GHz
Reflected by metallic objects, absorbed by dielectric materials, or transmitted from glass.