The reaction centre in PS II has an absorption maxima at

The reaction centre in photosystem II (PS II) has chlorophyll a molecules called P680, which have an absorption maximum at a wavelength of about 680 nm. These pigments are responsible for capturing light energy and exciting electrons that are used in the primary photochemical reaction of PS II, which involves the splitting of water molecules and the release of oxygen.

(1) The efficiency of photosynthesis significantly decreases when exposed to light with wavelengths exceeding 680
nm but a recent discovery reveals that sunflower leaves, while still connected to the plant, exhibit an initial decline in
photosynthetic activity beyond 680 nm. However, this decline is unexpectedly followed by a significant increase in activity at much longer wavelengths, allowing for detectable oxygen evolution to occur until reaching 780 nm.

(3) PS I is responsible for absorbing light with a wavelength of 700 nm, which is then used to transfer electrons from
plastocyanin to ferredoxin, leading to the production of ATP and NADPH.

(4) Chlorophyll a can absorb light with wavelengths of 430 nm for blue light and 660 nm for red light.