variation

The intensity of light is measured in Lux. It is found that the intensity of light varies as the inverse square of the distance between light source and point of measurement.
if at 10 meters, the intensity is 100 lux, what is the intensity of the light at 15 meter distance.



Answer:
Hint:

I α 1/D²

So, I x D² = Constant

Or, I₁ x D₁² = I₂ x D₂²