A certain lightbulb has a tungsten filament with a resistance of 28 Ω when cold and 144 Ω when hot.
If the equation R = R0 [1 + α ∆T ]
can be used over the large temperature range involved here, find the temperature of the fila- ment when it is hot. Assume that α , the tem- perature coefficient of resistivity of tungsten, is0.0045(◦C)−1 andthatthetemperatureof the cold filament is 17◦C.
Answer in units of ◦C.
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