The intensity of illumination from the light source varies inversely with the square of the distance from the light source when photoelectric sale is placed 8 inches from a light source intensity is 12 lm then it is moved so that it is receives only three loans how far is it from the light source

Inverse variation:

y - the intensity of illumination, x - the distance from the light source

When the distance is 8 inches, the intensity is 12 lm.


When the distance is x inches, the intensity is 3 lm.

The distance can't be a negative number, so x=16.

The photoelectric cell is 16 inches from the light source.