Degradation of Chemicals by Light

Other aspects of the effects of light are best described by invoking its particle nature. Each quantum of light, called a photon, possesses an energy equal to E, 

The actual distribution of light in water is complex, affected not only by the light s wavelength composition and intensity (intensity can be thought of as 

The extinction coefficient 17 may be calculated from measurements of I made by a light meter. The Secchi disk is another time-honored device for estimating light penetration in a lake. In 1865, P. A. Secchi developed this method, which was subsequently used aboard the papal yacht, S. S. L immacolata Concezione. The Secchi disk is about 20 cm in diameter, col- 

What is the light intensity at 1-m depth in a lake, given an intensity of 3000 microeinsteins (/xE)/(m2 sec) just beneath the lake s surface and an extinction coefficient of 0.6/m If an aquatic plant has a light compensation point (the light intensity at which respiration rate equals photosynthetic rate) of 150 fiE/(m2 sec), what is the maximum depth at which the plant may be expected to grow  

To calculate the maximum depth at which the plant can grow, use Eq. [2-77] and solve for z- 

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