Does the Calvin cycle return ADP Pand NADP to the light reactions?
Yes, It transfers them back; it is a continuous cycle.
1. Calvin cycle takes place in the stroma and light- dependent reactions take place in the granum, also light is not required for all the reactions of Calvin cycle. 2. Calvin cycle assimilates CO2 to form organic compounds whereas in light reactions photolysis of water leads the formation of energy rich inorganic compounds.
In photosynthesis, the the electron transport chain is part of the light dependent reactions. The "light independent reactions" are the Calvin-Benson cycle and do not include an electron transport chain, but the Calvin Cycle cannot proceed without the ATP and NADPH produced during the light reactions.