(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A heating coil is to be made, from nichrome wire, which will operate on a 12 V supply and will have a power of 36 W when immersed in water at 373 K. The wire available has a cross-sectional area of 0.10 mm². What length of wire will be required?

(Resistivity of nichrome at 273 K = 1.08 x 10-6 Ωm.

Temperature co-efficient of resistivity of nichrome = 8.0 x 10-5 K-1.)

I think that "Resistivity of nichrome at 273 K = 1.08 x 10-6 Ωm." is meant to say 373K, I will ask tomorrow.

2. Relevant equations

ρ=ρ^{0}[1+α(T-T_{0}) ]

3. The attempt at a solution

Im thinking that ρ(resistivity) can be changed with P/I^2 then I^2 with V^2/R^2 so i would end up with P*R^2/v^2=ρ^{0}[1+α(T-T_{0}) ] or something like that, I really need some pointers on where to go.

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# Homework Help: Heating coil

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