the top of one of my plants leafs has started turning yellow??

the top of one of my plants leafs has started turning yellow? is this nitrogen deficiency?as i have given every plant the same food and the rest are fine?

Age of plant(s)? Lighting? R u in veg or flowering? Sounds like a N def, but added info would be useful, and pics would be even better, as they r worth a thousand words...

its prob nothing man, only worry if other leaves start to do the same thing. chances are one or two leaves are effected and nothing else is going to happen