The chlorophyll-$a$ molecule of Photosystem-$I$ absorbs light at a wavelength of $.........$ and the chlorophyll-$a$ molecule of Photosystem-$II$ absorbs light at a wavelength of $.........$ for maximum absorption.

$ATP$ 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.

Identify the correct pathway of electron transport in the $Z$-scheme.

The specific function of light energy in the process of photosynthesis is to

Which of the following is the site for the photolysis of water?

$DCMU$ ($3$-($3$,$4$-dichlorophenyl)$-1,1-$dimethylurea) is a chemical that acts as an inhibitor of photosynthesis. What is its specific mode of action?