well this positiion shud be drawn anyway doesnt matter what color squares the pawns are on with the opposite colored bishops its a draw. But it depends on the position for deciding to put your pawns on the same color squares as your bishop or not.
Bishop pair
My impression of general guidelines, as they have been explained to me, is that in the middlegame, the Pawns should be on the opposite color squares of the Bishop. This defines the Bishop as a good Bishop, which means that it has good mobility. If the Pawns were on the same color squares as the Bishop, then it would be a bad Bishop, because its mobility would be reduced.
However, in the endgame, the Pawns should be on the same color as the Bishop. The logic here is that since so few pieces are on the board to defend those Pawns, the Bishop is needed to defend them from attack. However, one should, of course, take care that those Pawns do not become frozen on those same-color squares and therefore unable to advance. In the above diagram, if Black's Pawns are locked onto those dark squares, then White can dominate the light squares, as paulgottlieb explained.
So in the endgame, the Bishop and Pawns need to be balanced. But in general, the Bishop does well to defend Pawns occupying the Bishop's own squares, while the King aids in advancing them to--and through--the other-color squares.
Once again, these points pertain only to the most general of scenarios and in no way are intended to apply to all positions or circumstances. Many exceptions apply to these explanations, but this is according to what I have read and studied appertaining to general positional Bishop/Pawn maneuvering.
if i have a dark sq bishop why do i put my pawns to light sq i dont understand if my opponet have a light sq bishop i am unable to protect them isnt that correct see this?