50 watt light, how close?

how close do i have a 50 watt bulb to my plant, just one plant. i dont want to burn them so how many inches. my plant looks like this right now
View attachment 73006

thanks 4 any help

my journal is here: https://www.rollitup.org/grow-journals/51897-anthony-s-garden-first-grow.html

what kind of light?

its a mercury bulb

Well you normally want to have it around 2-4 inches away from your plants, but you also don't want to burn them... Experiment with it. if it starts to look like the plant is stretching then lower it, seems be be getting to hot/brunt higher it.