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.

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false

Answer

A

Explanation

Photosynthetic pigments absorb visible part of the radiation (i.e. 380 mu and 760 mu). If light at 680 nm is supplemented with the light of shorter wavelength the quantum efficiency in red can be restored to normal and a wavelength of 680 nm and above this phenomenon is called red drop