Which wavelength of light is best absorbed by chlorophyll?

Chlorophyll is a pigment essential for photosynthesis in plants, and it primarily absorbs light from the blue and red portions of the electromagnetic spectrum. The peak absorption of light by chlorophyll occurs around 660 nm, which falls in the red light range. This wavelength is particularly effective for driving the photosynthetic process because it excites electrons in the chlorophyll molecule, facilitating the conversion of light energy into chemical energy.

The other wavelengths mentioned, although they might be absorbed to some extent, do not align with the optimal absorption peaks of chlorophyll. Wavelengths such as 500 nm and 550 nm are more associated with green light, which is actually reflected rather than absorbed by chlorophyll, giving plants their characteristic green color. The 485 nm wavelength is closer to blue light, which is also absorbed by chlorophyll but does not have the same peak absorption efficiency as 660 nm. Therefore, the choice of 660 nm is the most accurate in identifying the wavelength best absorbed by chlorophyll for effective photosynthesis.