What does the given figure represent?

The decrease in the yield of photosynthesis in the presence of red light becomes increased to normal when it is supplemented with blue light. This phenomenon is termed as

The photochemical reaction in the chloroplast is directly associated with ...

$ATP$ synthesis in chloroplasts and mitochondria is due to a proton gradient across the membrane. Select the correct statements with respect to $ATP$ formation in chloroplasts:
$(a)$ Protons accumulate in the lumen of the thylakoid.
$(b)$ Splitting of water occurs on the inner side of the membrane.
$(c)$ Protons accumulate on the stroma side of the chloroplast.
$(d)$ $NADP$ reductase is located on the stroma side of the membrane.

$ADP + \Pi = ATP$ formation in grana is called......

The reaction centre in $PS$ $II$ has an absorption maxima at $............\,nm$.