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Radiant Energy Formula

The Radiant heat energy is a notion which is rather more nicely explained by Stefan’s law. This law elucidates how the heat is radiated! It states that, The amount of heat which is radiated (E) by a flawless black body for a second in a provided unit area is directly related to the fourth power of its absolute temperature (T).

The Radiant heat energy formula is articulated as,

α T4


E = σ T4

Stefan’s constant (5.67 × 10−8−8 W/m2/K4) is σ ,

radiant energy is E,

absolute temperature is T.

Radiant Energy Solved Problems

Some of the solved numerical based on Radiant Energy is provided underneath:

Problem 1: The surface temperature of the moon in the daytime is 123 Celsius. Compute the radiant heat energy for 1meter square area.

Known: T (Temperature) = 123 C = 123 + 273 K = 396 K

σ (Stefans Constant) = 5.67 × 10−8−8 W/m22/K44

Radiant energy, E = σ T44

E = 5.67 × 10−8−8 W/m2/K4 × (396)4

E = 1394.32.

Thus, the radiant heat energy is 1394.32. 

Problem 2: If the radiant energy of the body is 129.34, calculate its surface temperature.



E (Radiant energy) = 129.34,

σ (Stefans Constant)  = 5.67 × 10^-8 W/m2/K4

Radiant energy, E = σ T4

Thus, the temperature of the surface is 218.54 K.