What happens when light strikes the retina in the human eye? a. optic fibers send light to the brain. b. chemicals react to develop a photographic image. c. light-sensitive cells send impulses to the brain. d. an image is projected on the lens of the eye.

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.