Question: 102 The reaction centre in PS II has an absorption maxima at
(1) 660 nm
(2) 780 nm
(3) 680 nm
(4) 700 nm
Answer: Option (3)
Explanation:
Photosystem II is a pigment system involved in the light reactions of photosynthesis.
The reaction centre of Photosystem II contains a special pair of chlorophyll a molecules known as P680.
The term P680 indicates that these chlorophyll molecules absorb light maximally at a wavelength of 680 \, \text{nm}.
When light of this wavelength is absorbed, electrons are excited and transferred to the primary electron acceptor.
This initiates the electron transport chain and leads to photolysis of water.
Hence, the absorption maximum of the reaction centre in Photosystem II is 680 \, \text{nm}.