Under controlled darkened conditions in the laboratory, a light receptor cell on the retina of a person's eye can detect a single photon of light of...

Under controlled darkened conditions in the laboratory, a light receptor cell on the retina of a person's eye can detect a single photon of light of wavelength 505 nm and having an energy of 3.94×10−19 J . We shall assume that this energy is absorbed by a single cell during one period of the wave. Cells of this kind are called rods and have a diameter of approximately 2.00×10−3 mm.