Resistance Differences: Nichrome vs. Copper Wire

[ellieee]

Homework Statement

explain one electrical property of nichrome that makes it suitable to be used as a heating element?

Relevant Equations

nil

i don't understand the answer:
Nichrome has a higher resistance than copper wire. There is a greater potential
difference across the nichrome than the copper wire.
From ,the resistance of nichrome is low enough such that there is significant power
output.
^ i feel like the bold parts contradict each other?
and i don't understand why they are comparing the potential difference across nichrome with p.d across copper wire.

 

[kuruman]

I don't understand the answer either. If I were to choose between copper and nichrome to make a heating element, I would start with the consideration that each element would be hooked up to a household current outlet that provides constant voltage, say 120 V. I am not sure where the "greater potential difference across the nichrome wire" stated in the answer comes from. Furthermore, before plugging in either element to the outlet, I would consider that the current through the outlet is limited by a 20 A circuit breaker.

 

[berkeman]

I found this page that seems to do a pretty good job of describing heating element design and why the choice of nichrome over copper is good:

https://www.explainthatstuff.com/heating-elements.html

And I suspect that part of the reason may have to do with the impedance of the AC Mains power line...

http://www.powerlines.com/clips/pq2kdoc.pdf

@anorlunda may have better comments...

 

[kuruman]

And I suspect that part of the reason may have to do with the impedance of the AC Mains power line...

Maybe you don't need to go as deep as that. Nichrome's resistivity is about 67 times that of copper while its mass density is 8400 kg/m³ compared with 8960 kg/m³ for copper. So a nichrome wire of the same gauge and length as a copper wire will be slightly lighter, have roughly the same dimensions about 60 or so times the resistance of the copper wire.

I still don't understand the answer in #1. It seems that whoever wrote it is conflating resistance with resistivity.