They actually are 380-750nm is the visible range. That said one lumen is approx 3.8×1015 photons and an LED bulb produces 75-110 lumens per watt. It seems like the original poster meant that we are not capable of detecting this with the naked eye even though it is theoretically in the right range.
They actually are 380-750nm is the visible range. That said one lumen is approx 3.8×1015 photons and an LED bulb produces 75-110 lumens per watt. It seems like the original poster meant that we are not capable of detecting this with the naked eye even though it is theoretically in the right range.
https://physics.stackexchange.com/questions/880/how-many-pho...
https://www.voltlighting.com/learn/lumens-to-watts-conversio...
Clarification,
First I wrote, "Light of those wavelenghts is not invisible to humans."
I wanted to change it to, "Light of those wavelenghts is visible to humans."
But I messed up and it says what it says now, can't edit it further but I meant the opposite thing.