1. What Is The Emissive Power Given Radiation Intensity For Diffusely Emitting Surface?

The emissive power for a diffusely emitting surface is calculated from the radiation intensity using the formula \( E_{emit} = I_e \times \pi \). This relationship is fundamental in radiative heat transfer, where a diffuse surface emits radiation equally in all directions.

2. How Does The Calculator Work?

The calculator uses the formula:

Where:

• \( E_{emit} \) — Emitted Radiation (W/m²)
• \( I_e \) — Radiation Intensity (W/m²·sr)
• \( \pi \) — Archimedes' constant (≈ 3.141592653589793)

Explanation: For a diffusely emitting surface, the total emissive power is simply the radiation intensity multiplied by π, derived from integrating the intensity over the hemisphere.

3. Importance Of Emitted Radiation Calculation

Details: Accurate calculation of emitted radiation is crucial in thermal engineering, climate science, and materials science for determining heat transfer rates, energy balance, and surface properties.

4. Using The Calculator

Tips: Enter the radiation intensity in W/m²·sr. The value must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What is a diffusely emitting surface?
A: A diffusely emitting surface is one that radiates energy equally in all directions, following Lambert's cosine law.

Q2: Why is π multiplied with the intensity?
A: The factor π comes from the integration of radiation intensity over the hemisphere for a diffuse surface.

Q3: What are typical units for these quantities?
A: Radiation intensity is measured in W/m²·sr (watts per square meter per steradian), and emitted radiation in W/m² (watts per square meter).

Q4: Can this formula be used for all surfaces?
A: This formula is specifically valid for ideal diffuse surfaces. For specular or other surface types, different relationships apply.

Q5: How does this relate to blackbody radiation?
A: A blackbody is a perfect diffuse emitter, so this relationship holds exactly for blackbody radiation.