Question

If a copper wire has a resistance of 19.2 Ω at a temperature of 22.0 oC, what resistance does it have at 79.7 oC? (Neglect any change in length or cross-sectional area resulting from the change in temperature.)

Answer 1

ΔR=αR0ΔT.
the law is for resistivity, but because length and area will be the same then you can convert resistivity to resistance. alpha is a constant

Answer 2

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html
if you used the constant in the above link
\[r-19.2 = \alpha \times 19.2 \times ( 57.7)\]
the alpha should be given

Answer 3

I guess I am still confused, I don't think alpha is given

Answer 4

http://www.cirris.com/learning-center/testing-guidelines/special-topics/177-temperature-coefficient-of-copper
The information here gives you the temperature coefficient of resistance for copper, and gives examples of calculations that show you how to solve your question.

Answer 5

Any way alpha should mention in previous problem or in a table in your book.