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Unformatted text preview: nvection cooling only with a convection coefficient of . A ¼ Watt resistor is surrounded by still air at room temperature (20 °C). The resistor is approximately cylindrical with a length of 20 mm and a radius of 1 mm. How hot will it get if operated at the maximum rated power level, assuming a convection coefficient of ? Express your answer in Celsius and Fahrenheit. In deriving the Preece equation for fusing current it is assumed that thermal radiation is the dominant mechanism of heat transfer. For very thin wires made from metals with a low melting temperature, convection heat transfer may be dominant. Derive a modified version of the Preece equation for this extreme, assuming . You should again find an equation of the form , but the exponent is different. Calcu...
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 Fall '08
 York

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