PS II Reaction Centre & 680 nm Light — NEET Biology
✅ Asked in NEET 2023The reaction centre in PS II has an absorption maxima at (NEET 2023)
The reaction centre in PS II has an absorption maxima at (NEET 2023)
Answer & NCERT explanation
Correct answer: A — 680 nm
Photosystem II reaction center has absorption maxima at 680 nm, hence called P680. According to NCERT, this is the wavelength at which PS II chlorophyll molecules absorb light most efficiently. PS I has absorption maxima at 700 nm (P700). The other wavelengths (660 nm, 780 nm) are not characteristic absorption maxima for photosystems.
Read more NCERT concept on the PYQ
In photosystem II the reaction centre chlorophyll a absorbs 680 nm wavelength of red light causing electrons to become excited and jump into an orbit farther from the atomic nucleus. These electrons are picked up by an electron acceptor which passes them to an electrons transport
NEET tests whether students know that Photosystem II's reaction centre chlorophyll a (P680) absorbs 680 nm red light, which excites electrons to higher energy states. These excited electrons are then transferred to an electron acceptor and passed along the electron transport chain. The common mistake is confusing P680 with P700 (PS I's reaction centre), or thinking PS II absorbs different wavelengths. Remember: P680 = 680 nm = PS II; P700 = 700 nm = PS I. This concept is fundamental for understanding light-dependent reactions and energy transfer during photosynthesis.
What does NCERT say about photosystem II reaction centre?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.