Where does the process of photophosphorylation occur in the chloroplast?

What happens when the proton gradient breaks down?

$X -$ In $PS-I$,Chlorophyll $a$ has an absorption peak at $680\, nm$.
$Y -$ In $PS-II$,it has an absorption maximum at $700\, nm$.

In which process is $NADP^+$ reduced to $NADPH$?

The process of $ATP$ synthesis during photosynthesis is known as:

In photosystem $II$,the reaction center chlorophyll $a$ absorbs $680 \, nm$ wavelength of ...... causing electrons to become excited and jump into an orbit.