Answer to Question #172562 in Physics for Diocos

Question

Radiation makes it impossible to stand close to a hot lava flow. Calculate the rate of heat transfer by radiation from 1.21 m² of 1276 ºC fresh lava into 37 ºC surroundings, assuming lava’s emissivity is 1.00

Answer 1

Convert temperature in degree Celsius to Kelvin:

T₂=1276+273.15=1549.15 K,

T₁=37+273.15=310.15 K.

The net rate of heat radiation is

$$\frac{Q}{t}=A\epsilon\sigma(T_2^4-T_1^4),\\\space\\ \frac{Q}{t}=1.21·1·5.67·10^{-8}(1549.15^4-310.15^4)=\\=394500\text{ W}.$$