If the oort cloud contains 1012 comets, and ten new comets are discovered coming close to the sun each year, what percentage of the comets have been “used up” since the beginning of the solar system?

The solar panels used by mark function because of the photoelectric effect. light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. at night on mars, no light will fall on the solar cells and no electric current will be generated. according to your notes, what type of light is typically needed to cause the photoelectric effect? a)visible b)ultraviolet c)infrared