Question

If the calvin cycle slows down, what will happen to the rate of o2 production in ps ii, and why?

Answer 1

If the Calvin cycle slows down, THE RATE OF OXYGEN PRODUCTION IN PS II WILL BE REDUCED. 
This is because, the light reaction depends on the dark reaction to occur. If the Calvin cycle slows down, the light cycle will have less ADP and NADP+ to work with and this will slow down the production rate of the photosynthetic reaction.