Answer:
The main differences betwen rod and cone cells are their sensitivity and visual acquity.
Rod cells are highly senstive. They can respond to low light intensities and hence allow us to see at night, although only in black and white. This is due to retinal convergence, this is where many rod cells share a bipolar cell, which is connected to a sensory neurone. In order for a generator potential to be produced rhodopsin, the photochemical pigment must be broken down. Due to summation of the rod cells, this threshold is overcome and hence a generator potential is produced, a nerve impulse is hence sent to the brain via the optic nerve and the light stimulus is detected.
Cone cells have high visual acquity (accurateness). This is because each cone cell is connected to its own bipolar cell and hence its own sensory neurone. Hence when one cone cell is stimulated and iodopsin (photochemical pigment) is broken down, a generator potential is produced. Therefore each cone cell that is stimulated sends a nerve impulse to the brain and hence separate stimuli can be detected.