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Radiation Intensity for emitted radiation is the rate at which radiation energy is emitted in a direction per unit area normal to this direction and per unit solid angle about this direction. It is a fundamental concept in radiative heat transfer and optics.
The calculator uses the formula:
Where:
Explanation: For a diffusely emitting surface, the radiation intensity is uniform in all directions and is related to the emissive power through the constant π.
Details: Accurate calculation of radiation intensity is crucial for thermal radiation analysis, heat transfer calculations, optical system design, and various engineering applications involving radiative energy transfer.
Tips: Enter emissive power in W/m². The value must be positive and valid. The calculator will compute the radiation intensity in W/m²·sr.
Q1: What is the difference between emissive power and radiation intensity?
A: Emissive power is the total radiation energy emitted per unit time per unit area, while radiation intensity is the radiation energy emitted per unit time per unit area per unit solid angle in a specific direction.
Q2: Why is π used in this formula?
A: The factor π comes from the integration over the hemisphere for a diffusely emitting surface, where the radiation intensity is uniform in all directions.
Q3: What are typical units for radiation intensity?
A: Radiation intensity is typically measured in watts per square meter per steradian (W/m²·sr).
Q4: Does this formula apply to all types of surfaces?
A: This specific formula applies only to diffusely emitting surfaces (Lambertian surfaces) where radiation intensity is constant in all directions.
Q5: How does radiation intensity relate to radiosity?
A: Radiosity includes both emitted and reflected radiation, while radiation intensity specifically refers to the emitted radiation component.