Light Intensity Calculator
🌿 Photosynthesis & respiration. Use the Light intensity (inverse square law) formula to find relative light intensity, distance from the lamp: pick the value you want, type the others, and the answer updates as you go.
Double the distance and the light is a quarter as bright.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Relative light intensity | 1/cm² |
| Distance from the lamp | cm |
Worked example
Find the relative light intensity when Distance from the lamp = 20 cm.
Using light intensity ∝ 1/d²: Relative light intensity = 0.0025 1/cm².
Frequently asked questions
What is the formula for Light intensity (inverse square law)?
light intensity ∝ 1/d². Double the distance and the light is a quarter as bright.
What do the letters stand for, and what units are used?
Relative light intensity in 1/cm², Distance from the lamp in cm.
How do you calculate relative light intensity?
Put the values into light intensity ∝ 1/d². For example, with Distance from the lamp = 20 cm, relative light intensity = 0.0025 1/cm².
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (relative light intensity, distance from the lamp) and fill in the others: it rearranges the formula for you.
