Answer:
a) The rate at which the cube emits radiation energy is 704.48 W
b) The spectral blackbody emissive power is 194.27 W/m²μm
Step-by-step explanation:
Given data:
a = side of the cube = 0.2 m
T = temperature = 477°C
Wavelength = 4 µm
a) The surface area is:

According Stefan-Boltzman law, the rate of emission is:

b) Using Plank´s distribution law to get the spectral blackbody emissive power.
