Answer:
the required electrical power when the room air and surroundings are at 30°C.= 52.51822 Watt
Explanation:
Power required to maintain the surface temperature at 150°C from 20°C
P= εσA(T^4-t^4)
P= power in watt
ε= emissivity
A= area of surface
T= 150°C= 423 K
t= 20°C= 303K
/sigma= 5.67×10^{-8} watt/m^2K^4
putting vales we get
[tex]= 0.8\times5.67\times10^{-8} \pi\frac{0.25^4}{4}(423^4-303^4)[/tex]
P=52.51822 Watt
the required electrical power when the room air and surroundings are at 30°C.= 52.51822 Watt
