Advanced Radiant Flux Input Panel
Choose a physics relation, enter values with units, and compute radiant flux in watts or another selected output unit.
Formula Used
Radiant flux, written as Φe, is the rate of radiant energy transfer. Its SI unit is the watt, which equals joules per second.
| Mode | Formula | Meaning |
|---|---|---|
| Intensity Mode | Φe = Ie × Ω |
Use radiant intensity and the solid angle receiving the radiation. |
| Irradiance Mode | Φe = Ee × A |
Use irradiance over a known illuminated area. |
| Radiance Mode | Φe = Le × A × cos(θ) × Ω |
Useful for a uniform radiance case with projected area. |
| Photon Mode | Φe = N × h × c / λ |
Convert photon count rate into optical power using wavelength. |
| Energy-Time Mode | Φe = Q / t |
Find average radiant flux from delivered energy over time. |
How to Use This Calculator
- Select the calculation mode that matches the data you already know.
- Enter each value and choose its correct unit from the dropdown list.
- Pick the output unit for the final radiant flux display.
- Press Calculate Radiant Flux to show the result above the form.
- Use the CSV or PDF buttons to save the computed output.
Example Data Table
These sample cases demonstrate the main calculation paths available in the calculator.
| Method | Inputs | Radiant Flux |
|---|---|---|
| Intensity × Solid Angle | 12 W/sr, 0.8 sr | 9.6 W |
| Irradiance × Area | 250 W/m², 0.04 m² | 10 W |
| Radiance Mode | 50 W/(sr·m²), 0.2 m², 30°, 0.5 sr | 4.330127 W |
| Photon Rate Mode | 3×10¹⁹ photons/s, 650 nm | 9.167751 W |
| Energy ÷ Time | 180 J, 15 s | 12 W |
FAQs
1. What is radiant flux?
Radiant flux is the total optical power carried by radiation. It measures energy transfer rate and is reported in watts.
2. How is radiant flux different from luminous flux?
Radiant flux measures physical optical power. Luminous flux weights light by human eye sensitivity, so it represents perceived brightness instead.
3. Why does angle matter in radiance mode?
The effective projected area changes with angle. As the surface tilts, the usable area becomes smaller through the cosine term.
4. Can this calculator be used for lasers?
Yes, especially with photon-rate, energy-time, or intensity inputs. Just make sure your source values and wavelength are accurate and consistent.
5. Why does wavelength affect the photon mode result?
Each photon carries energy equal to h×c divided by wavelength. Shorter wavelengths carry more energy, raising radiant flux for the same photon rate.
6. Which output unit should I choose?
Use watts for standard reporting. Smaller sources often read better in milliwatts or microwatts, while large systems may suit kilowatts.
7. Can radiant flux ever be negative?
Not in this calculator. Inputs describe magnitude-based physical quantities, so the tool expects positive values and practical geometry.
8. Does this replace full optical simulation?
No. It is a fast analytical calculator for common relations. Complex scattering, spectral variation, and spatial nonuniformity need deeper modeling.