What is the relationship between heat loss and resistivity in a cable?

AI Thread Summary
The relationship between heat loss and resistivity in a cable is explained through the formula R = p*l/A, where resistance (R) increases with length (l) and resistivity (p). Heat loss in a conductor is proportional to the current squared times the resistance (P = I^2R). A longer cable results in higher resistance, leading to increased heat generation. The discussion clarifies that while resistivity is important, the length of the conductor significantly impacts overall resistance and heat loss. Understanding these relationships is crucial for optimizing cable performance and safety.
dinhjeffrey
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Homework Statement



http://img710.imageshack.us/i/2631001.jpg/
#29

Homework Equations



p=I^2R
P=IV

The Attempt at a Solution


well, the answer is D, but i don't see why the length matters? can anyone find out the equation for this problem?
i thought it was B) cable B because it has more resistivity
 
Physics news on Phys.org
The resistance of a conductor can be found using the equation,

R = p*l/A

where R = resistance, p = resistivity, l = length of conductor, and A =cross sectional area of conductor.

Length matters because the longer a resistor is, the more it can obstruct the flow of charge.
 

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