Are the Latin words "negative", "nego" and "niger", "nox" are cognates? In accordance to bible, word is a light and its absence is a dark.
A few things first:
- "Negative" comes from negō; the photography meaning came millennia later and isn't really relevant to the etymology
- Negō comes from the negater nē plus the old word for "to speak", which looked something like *agjō—so nē is what's relevant here
Now, for the three words in question:
- Nē goes all the way back to PIE without change; it's also the source of English negatives like "un-", "not", "no," and "never" (which accumulated other morphemes through Jespersen's Cycle)
- Nox comes from PIE
*nokʷts, which might come from
- Niger's etymology is uncertain, but it might come from
So, it's possible that nox and niger are related, but it's not completely accepted. It's pretty clear that nē isn't related within the timeframe that we can reconstruct; anything before that is pure speculation.
P.S. In linguistics (and most other sciences), the Bible isn't generally considered a reliable source. While you may believe in it, many other people in the world do not, and it can't be backed up with evidence.