Q4. Assertion: the rate of photosynthesis is still high at about 460–500 nm, although chlorophyll a absorbs little light there. Reason: accessory pigments absorb light that chlorophyll a absorbs poorly and transfer the energy to chlorophyll a. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion: in NCERT Figure 11.3, chlorophyll b and the carotenoids absorb strongly at these wavelengths (NCERT pages 137–138).
Q5. From what do accessory pigments protect chlorophyll a?
From photo-oxidation (NCERT page 138).
Q6. In which two regions of the spectrum does chlorophyll a absorb most, and how does the rate of photosynthesis compare there?
The blue and the red regions; the rate of photosynthesis is also higher there (NCERT page 137).