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Inverse Square Law:
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The Inverse Square Law states that the intensity of light is inversely proportional to the square of the distance from the source. This principle applies to all forms of radiation that propagate evenly in all directions from a point source.
The calculator uses the Inverse Square Law equation:
Where:
Explanation: As distance from a light source increases, the intensity of light decreases by the square of that distance.
Details: Accurate light intensity calculation is crucial for lighting design, photography, stage production, and scientific experiments where precise illumination levels are required.
Tips: Enter initial intensity in lux and distance in meters. All values must be valid (intensity > 0, distance > 0).
Q1: Does this law apply to all light sources?
A: The inverse square law applies to point sources that emit light uniformly in all directions. It may not be perfectly accurate for directional light sources or in environments with significant reflections.
Q2: What are typical light intensity values?
A: Direct sunlight is about 100,000 lux, office lighting is typically 300-500 lux, and moonlight is about 0.1 lux.
Q3: How does this relate to photography?
A: In photography, this law explains why subjects need significantly more light when moved further from a light source, affecting exposure calculations.
Q4: Are there limitations to this law?
A: The law assumes a point source in a vacuum with no reflections or absorptions. Real-world conditions with reflective surfaces may produce different results.
Q5: How does distance affect light intensity in practical terms?
A: Doubling the distance from a light source reduces the intensity to one-quarter of its original value. Tripling the distance reduces it to one-ninth.