Radiation Rate of 0.1m Cube Metal at 200C

[Kyle North]

Homework Statement

At what rate does a 0.1m cube of metal with emissivity e=0.75 radiate energy if it is at a temperature of 200C?

Homework Equations

H=AeσT^4, σ=5.67 x10^-8

The Attempt at a Solution

I found the area of the cute to be A=(0.1m)^2=0.01m, and the turned 200C into 473K, but when I type them all in I get 21.28W and the answer is 128W?

 

[gneill]

How many faces does a cube have?

 

[Kyle North]

6.. thanks!

 

[SteamKing]

Also, (0.1 m)² = 0.01 m² Don't forget to square the units.