Question

A black body at a temperature of ${227}^0$C radiates heat energy at the rate of 5 cal/$c{m}^2$-sec. At a temperature of ${727}^0$C, the rate of heat radiated per unit area in cal/$c{m}^2$ will be

• A. 80
• B. 160
• C. 250
• D. 500

Answer 1

The correct option is A

80

$\frac{E_2}{E_1}={\left(\frac{T_2}{T_1}\right)}^4=\left(\frac{273+727}{237+227}\right)=\frac{(1000{)}^4}{(500{)}^4}=16\Rightarrow E_2=80$