Resistance depending on temperature

[lilaznjewel]

Homework Statement

At 30.3C, the resistance of a segment of gold
wire is 124.9 omega When the wire is placed in a
liquid bath, the resistance decreases to 97.5 omega
What is the temperature of the bath?
The temperature coefficient for gold is
0.0034 (C)−1 at 20C.
Answer in units of C.

Homework Equations

used R=Ro[1+alpha(t-to)

The Attempt at a Solution

I got -34.2, but the homework says its incorrect

 

[gneill]

Hmm. The numbers look okay to me. Did you include the units when you answered?

 

[lilaznjewel]

Hmm. The numbers look okay to me. Did you include the units when you answered?

yes do you think it could be wrong because of sigfigs so it be -34.22

 

[gneill]

How many significant figures do each of the provided numbers have?

 

[lilaznjewel]

To has 3
Ro has 4
R has 3
alpha has 4

 

[gneill]

Check http://www.usca.edu/chemistry/genchem/sigfig.htm" .

 

[lilaznjewel]

ok i put in -34.22 but, it is still wrong

 

[gneill]

-34.22 has four significant figures. The temperature coefficient has fewer.

 

[cupid.callin]

I'm getting something else ... its less than your answer

why not use the temp you got and find the resistance and match it with 124.9 ohm

 

[lilaznjewel]

I don't really understand what you are trying to say

 

[gneill]

The provided temperature coefficient for gold has two significant figures. Did you try your result with two significant figures?