Calculating Heat Flow Ratio of Two Water Tanks

[5carola5]

Homework Statement

There are two tanks with water, there are standing very close to each other. Tank 1 is having a temperature of 0 degrees and tank 2 is having a temperature of 10 degrees. The heatflow between the two is Q₁. Then tank two is getting a temperature of 100 degrees. That heatflow we will call Q₂. The question is: By what degree will the ratio Q2/Q1 chance?

Homework Equations

I don't know really...

The Attempt at a Solution

So I used Q=cA(T1⁴-T2⁴). c and A are some constants that are the same for both tanks so cA=C. Then I put the temperatures in the formula making it:
Q1=C*10⁴ and Q2=C*100⁴ Then deviding them to get: 100⁴/10⁴=1*10⁴ (the constant C disappears). So my answer would be 1*10⁴ And the answer is supposted to be 16, which sounds much more normal to me. But I have no idea how to get here...

 

[TSny]

What unit should you be using for T?

 

[5carola5]

celcius, sorry forgot to say

 

[TSny]

celcius, sorry forgot to say

Is it ok to use Celsius unit in the formula, or does the formula require that you use another unit?

 

[5carola5]

I don't really know extally, can try to do it in Kelvin as the last time I did it in celsius... let's see.

then it becomes: (373^4) / (283^4) = 3,018. That's also not alright, so it must be something else. Might be a total differend formula, I really don't know...

 

[TSny]

Did you also convert the 0 ^oC to Kelvin?

 

[5carola5]

aaaah I forgot ^^'
((373^4) - (273^4)) / ((273^4) - (283^4)) = -16,1... Oke thanks a lot ^^" That was pretty stupit of me... But I will not do that wrong again for quite some time :P

thanks again:)

 

[TSny]

We've all learned that lesson the hard way.