The human eye can detect light intensities as small as about 1 x 10^-23 W/m².
(a) What is the corresponding electric field amplitude?
(b) Suppose the eye senses this light by detecting the force on electrons inside a photoreceptor cell within the eye. What is the electric force exerted on an electron by the electric field found in part (a)?
(c) How does this force compare to the weight of an electron?