Inverse-square Law Calculator
☢ Nuclear & Decay. Use the Inverse-square law formula to find intensity 1, distance 1, intensity 2, distance 2: pick the value you want, type the others, and the answer updates as you go.
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 |
|---|---|
| Intensity 1 | no unit |
| Distance 1 | m |
| Intensity 2 | no unit |
| Distance 2 | m |
Worked example
Find the intensity 1 when Distance 1 = 1 m, Intensity 2 = 25, Distance 2 = 2 m.
Using I1 R1² = I2 R2²: Intensity 1 = 100.
Frequently asked questions
What is the formula for Inverse-square law?
I1 R1² = I2 R2².
What do the letters stand for, and what units are used?
Intensity 1, Distance 1 in m, Intensity 2, Distance 2 in m.
How do you calculate intensity 1?
Put the values into I1 R1² = I2 R2². For example, with Distance 1 = 1 m, Intensity 2 = 25, Distance 2 = 2 m, intensity 1 = 100.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (intensity 1, distance 1, intensity 2, distance 2) and fill in the others: it rearranges the formula for you.
