A nichrome heating element has a resistance of 12Ω at 25∘C. The temperature coefficient of resistivity for nichrome is α=0.00040∘C−1. If the element’s temperature rises uniformly to 225∘C while connected to a constant-voltage power supply, what is its resistance at the higher temperature?
a) 17Ω
b) 12Ω
c) 13Ω
d) 9.6Ω