New to growing, need some info about yield?

Hello, I see a lot of posts saying yield depends on the amount of light/watts right? So say you get around 1 gram per watt. Does that mean if I use a 1000 watt light with 1 plant, I will get the same yield as using a 1000 watt light on 2 plants? Is there a certain point where plants can absorb only so much light, hence making using X amount of wattage useless on just 1 plant?

There is only so much square footage you can cover. Max yields seem to be at 80 watts per square foot. Go big to grow big on air, containers and lights. Don't believe anything you hear or read and only about half of what you see in regards to promises by breeders..

Dude there is no point in using a 1000 watt for 1 plant that's just a waste of money and u gotta have a good plan of action to get 1 gram a watt but good luck I guess