Light Bulb Filaments
I want to know about the resistance of a filament light
bulb and a lenght of nichrome wire. I want to know what factors effect the
resistance of a light bulb and of a length of nichrome wire. I would also
like to know why the resistance of a nichrome wire is constant and the
resistance of a filament bulb will be varied.
The resistance of the nichrome wire depends on cross sectional area,
length, crystalline structure and purity, and temperature. For a wire of
constant manufacture, all of these variables remain the same, so the
resistance is constant. If you heat it as the filament of a lightbulb, the
temperature changes, and therefore, the resistance changes.
Nathan A. Unterman
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Update: June 2012