Question

Two black bodies at 327${}^o$C and 627${}^o$C are suspended in an environment at 27${}^0$C. The ratio of their emissive powers is:

• A. $15:8$
• B. $16:3$
• C. $3:16$
• D. $5:8$

Answer 1

The correct option is C $3:16$

We know that: $E=\sigma T^{4}watt/{meter}^2$

$E_1=5.67\times {10}^{-8}\times {600}^4=7348.32w/m^2$

$E_2=5.67\times {10}^{-8}\times {900}^4=37200.87w/m^2$

So ratio will be: ${\frac{E_1}{E}}_2=\frac{3}{16}$