Light hitting Photosystem I (PSI) provides energy to produce NADPH (nicotinamide adenine dinucleotide phosphate).

Here's a breakdown:

* Photosystem I (PSI): A protein complex in the thylakoid membrane of chloroplasts that absorbs light energy.

* Light Energy: The light energy excites electrons within PSI.

* Electron Transport Chain: These excited electrons move through an electron transport chain.

* NADP+ Reduction: The energy from the electrons is used to reduce NADP+ (nicotinamide adenine dinucleotide phosphate) into NADPH.

NADPH is a crucial reducing agent in the Calvin cycle, the next stage of photosynthesis, where it provides the necessary electrons to convert carbon dioxide into sugars.