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When the reaction-centre chlorophyll of PS II absorbs red light of 680 nm, its electrons

(a) return to ground state, releasing only heat Your answer
(b) are used up in splitting CO₂ in the stroma Your answer
(c) are passed straight to NADP⁺ in the stroma Your answer
(d) are excited and taken up by an electron acceptor Correct

Your answer: Correct answer: (d)

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Explanation

Why (d) is correct

When P680 absorbs light, its electrons are excited to a higher energy level and are taken up by an electron acceptor.

Why the other options are wrong

(a) · your answer In a working photosystem the energy is not just lost as heat; electrons leave the reaction centre.
(b) · your answer CO₂ is not split; it is reduced in the Calvin cycle.
(c) · your answer Electrons from PS II reach NADP⁺ only through the transport chain and PS I.

NCERT point: The electrons lost by P680 are replaced by electrons from water.

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