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The Heating of Nichrome Wire in a toaster 
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#1
Sep2409, 03:12 PM

P: 23

1. The problem statement, all variables and given/known data
A toaster with a Nichrome heating element has a resistance of 70 ohms at 20^{o}C and an initial current of 1.6 A. When the heating element reaches its final temperature, the current is 1.39 A. What is the final temperature of the heating element? 2. Relevant equations V=IR [tex]\alpha[/tex]=([tex]\rho[/tex][tex]\rho[/tex]_{o})/[tex]\rho[/tex]/(T_{f}T_{o}) 3. The attempt at a solution I know that the voltage will remain constant therefore: I_{o}*R_{o}=I_{f}*R_{f} I also know that Nichrome's [tex]\alpha[/tex]=100e8 but I don't really know where to go from here 


#2
Sep2409, 03:39 PM

P: 1,398

from [tex]
\alpha = \frac {\rho  \rho_0} {\rho} (T_f  T_0) [/tex] try to derive an equation for R as a function of R_0, T_0, T_f and [itex] \alpha [/itex] you know the new R from ohms law. The temperature coefficent of nichrome is [itex] 4 *10^{4} K^{1} [/itex] 


#3
Sep2409, 03:43 PM

P: 23

So am I going to be looking at resistivity then? such as [tex]\rho[/tex]=R*A/L ??



#4
Sep2409, 04:20 PM

P: 1,398

The Heating of Nichrome Wire in a toaster



#5
Sep2409, 05:17 PM

P: 23

C as in capacitance? How do I find that?



#6
Sep2409, 05:31 PM

P: 1,398




#7
Sep2409, 05:33 PM

P: 23

would that constant be in my physics book somewhere?



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