A heating element has a resistance of 100Ω at room temperature. When it is connected to a supply of 220 V , a steady current of 2 A passes in it and temperature is 50 0 o C more than the room temperat

Question

A heating element has a resistance of 100Ω at room temperature. When it is connected to a supply of 220 V , a steady current of 2 A passes in it and temperature is 50 0 o C more than the room temperature. The temperature coefficient of resistance of the heating element is

TestHub · Accepted Answer

Resistance of heating element after temperature increases by $50 0^{o} C = \frac{220}{2} = 110Ω$ (from Ohm's law). The new resistance is related to the temperature coefficient of the heating element as $110 = 100 (1 + α 500)$

$α = \frac{10}{100 \times 500}$ $\Rightarrow α = 2 \times 1 0^{- 4} \circ C^{- 1}$

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