On the LightFalloff node, the Quadratic channel is your Inverse Square, a typical feature found in most of the light sets.  The Linear and Constant channels will deliver a full blast of light like an exploding sun.  Whenever I use this for node arrangement with emitting objects, I attach a Blackbody node to the Color channel of the Emission node to simulate different types of lighting from candlelight to incandescent through LED to mid- to late morning/afternoon.  In some cases, the tint is very slight but more realistic than faking a color chip.