How many cfl lights for grow box?

A question from a fellow grower:

I have question,i will be so pleased if you inform me,
I have made a grow box in size of 1/20×1/20 cm,
How many 40w cfl light do i need for it?

If you mean 120cm x 120cm then that’s almost 16 square feet,you want 50 watts per square foot so 800 watts