Question

Assertion : There is a decrease in photosynthesis, if the photosynthetic cells are illluminated by light of `P_(680)` nm or more wavelength.
Reason : In red drop phemonmeno the rate of photosynthesis decreases.
A. If both the asserition and the reasion are true and the reason is a correct explanation of the assertion
B. If both the assertion and reasoni s not a correct ecplanation of the assertion
C. If the assertion is true but the reason is false
D. If both the asseertion and reason are false

Answer 1

Correct Answer - B
Although the efficiency of photosynthesis is uniform over most of the spectrum, it declines significantly in the red, i.e., at wavelength of 680 nm and above. This phenomenon is called red drop. However, it was shown by Emerson that if light at 680 nm is supplemented with light of a shorter wavelength (lt 600 nm). the quantum efficiency of photosynthesis in the red can be restored to normal.