Question

A heating element using nichrome connected to a 230 V supply draws an initial current of 3.2 A which settles after a few seconds to a steady value of 2.8 A. What is the steady temperature of the heating element if the room temperature is 27.0 °C and the temperature coefficient of resistance of nichrome is 1.70 × 10^–4 °C^–1 ?

Answer 1

Given: V = 230 V, I₀ = 3.2A, I = 2.8A, T₀ = 27°C, α = 1.70 × 10^–4 °C^–1 .

Using equation R = R₀ (1+ α ∆T)

i.e V/ I = {V/ I₀ } [1 + α ∆T] 1/2 M

And solving ∆T = 840 , i.e. T = 840 + 27 = 867°C