(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

What maximum power can be radiated by a 14cm -diameter solid lead sphere? Assume an emissivity of 1

Answer in two sig fig.

2. Relevant equations

( Q / delta t) = e*σ*A*T^4

e=1

σ=5.67*10^-8 W/m^2*K^4 Stefan-Boltzmann constant (<--- who happens to be my great grandpa ;) )

A= (4*pi*r^2) = (4*pi*0.07m^2)

T= 273K (I think)

3. The attempt at a solution

( Q / delta t) = e*σ*A*T^4 = (1)*(5.67*10^-8w/m^2*k^4)*(4*pi*0.07m^2)*(273k^4) = 19 Watts

They never gave the temperature so I was assuming it would be 273. They do mention that it is a lead sphere and I have not used any values for the physical properties of lead in my equation. I think I am probably off on the temperature. Does anyone have some input? This is masteringphysics homework so I need use their values or I could get my answers wrong due to different values for the constant. I am not asking for answer... just guidance... I think I am very close. I have 48 hours left so any input asap would be appreciated.

-Eddie

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# Homework Help: Heat-Transfer Mechanisms (HARD)

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