Chapter 11 Fundamentals of Thermal Radiation 11-9C Microwaves in the range of 10are very suitable for use in cooking as they are reflected by metals, transmitted by glass and plastics and absorbed by food (especially water) molecules. Thus the electric energy converted to radiation in a microwave oven eventually becomes part of the internal energy of the food with no conduction and convection thermal resistances involved. In conventional cooking, on the other hand, conduction and convection thermal resistances slow down the heat transfer, and thus the heating process. 2to 10 m5μ11-10 Electricity is generated and transmitted in power lines at a frequency of 60 Hz. The wavelength of the electromagnetic waves is to be determined. AnalysisThe wavelength of the electromagnetic waves is λ==×=×cv2 998 10608. m/sHz(1/ s)4.997 10 m6Power lines 11-11 A microwave oven operates at a frequency of 2.8
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