Radiation from a cube at 189 °C

[Tinkylo]

Homework Statement

A cube at 102 °C radiates heat at a rate of 64 J/s. If its surface temperature is increased to 189 °C, the rate at which it will now radiate is closest to

Relevant Equations

P2/P1=(T2/T1)^4

I have tried to use the above equation.
P2/64=(189/102)^4
P2=754.4431
But I don't know why the answer is wrong. Please help!

 

[Gaussian97]

Wath out your units

 

[phinds]

Homework Statement:: A cube at 102 °C radiates heat at a rate of 64 J/s. If its surface temperature is increased to 189 °C, the rate at which it will now radiate is closest to
Relevant Equations:: P2/P1=(T2/T1)^4

I have tried to use the above equation.
P2/64=(189/102)^4
P2=754.4431
But I don't know why the answer is wrong. Please help!

First, this does not appear to be a complete problem statement since you trail off with "the rate at which it will now radiate is closest to " which looks like it should be followed by choices, plus you say the answer is wrong but you give no indication WHY you think it is wrong, which again seems to imply that there are choices for the answer and your answer isn't any of them.

Second, that subject line is terrible. Of course you have a problem or question. That's what the homework section is for, but why make people guess what KIND of problem instead of saying something like "need help with a thermodynamics problem" ?

 

[Orodruin]

Relevant Equations:: P2/P1=(T2/T1)^4

The temperatures here are absolute temperatures.

 

[berkeman]

Second, that subject line is terrible. Of course you have a problem or question. That's what the homework section is for, but why make people guess what KIND of problem instead of saying something like "need help with a thermodynamics problem" ?

Agreed. I fixed the thread title to make it actually describe the problem, instead of being an empty statement "Please help with the Question! ".