Energy is transferred through a solid by if there is a
between the ends of it.
Liquids and solids transfer energy
by because the particles can
Energy is transferred much
through an insulator
than it is through a conductor.
Tore

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?