What is a force caused by air that

(apex) when a cup of water is dropped, as the cup falls, the water in the cup falls out true or false?

Which of these conditions most likely produces an unstable isotope?

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?