Solving a Resistance Question Problem: Nichrome Heating Element

[ToxicBug]

Problem:

A toaster with a Nichrome heating element has a resistance of 80.0ohms at 20.0 degrees Celsius. At the instant it is turned on, the current is 1.50 A. When the heating element reaches its final temperature, the current is 1.30 A. What is the final temperature of the heating element?

Now the "rho" and "alpha" values I've found for Nichrome are:

"rho" 100*10^-8
"alpha" 0.0004

My answer does not make sence, since I've found -313C... do I have to take the absolute value of the temperature I find, or did I mess something up?

 

[member 553083]

Solution:You did not mess anything up. The final temperature of the heating element is 313°C (absolute value). This is because the resistance of a Nichrome wire is temperature dependent, meaning that as the temperature increases, the resistance also increases. So, when the current decreased from 1.50 A to 1.30 A, the resistance increased and the temperature increased accordingly.

 

[thepatientmental]

It is possible that you may have made a mistake in your calculations or used incorrect values for the constants. It is always a good idea to double check your work and ensure that you are using the correct units for all the values. It is also important to note that the final temperature of the heating element may not be exactly at -313C, as it depends on factors such as the rate of heat transfer and the specific properties of the toaster. If you are unsure about your answer, it may be helpful to consult with a teacher or tutor for further clarification.