If you know how much heat a bar is putting out, what is the temperature at the center of the bar?
Meaningless question without more information. You could have a moderate-heat bar with a large mass putting out the same amount of heat as a hotter bar of lower mass, and they would have different temperatures.
If this is a homework problem, you need to show the exact question and show your own attempt at a solution.
Not really my field but I agree with phinds. More info needed.
If you know the power (aka heat) and the emissivity you might be able to use that to work out the surface temperature of the bar. Then if you know the thermal conductivity between the core and the surface you might be able to work out the core temperature. Some assumptions are required - such as it all being in steady state eg something is heating the core of the bar to compensate for the heat losses.
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