It depends on how dark the room is. If the room is well lit, the light had better be really close to do any good. It works if you have it pretty near the object you want to photograph and the object isn't too big. For example, you could use it to light a plate of food, but not to light a large piece of furniture, however.
Not in feet. However, I'm using this light to make a photographic inventory of my household items. I've taken perhaps 100 photos so far, both close and across a room. All have been satisfactory although a few have had to be tweeked a bit in Photoshop for brightness/contrast, for both being a bit too bright or a bit too dim. I doubt that I'd use it for professional photography but for 'point and shoot' it works well for me.