Cylinder
its a lens...1 curved edge = a circle, 1 flat surface = back, 1 curved surface = front. (these are used in some battery-less flashlights, as an example.)
a giant or small cone
1 because all of the shape is curved except for the flat surface on the bottom
The description given fits that of a cylinder.
A cone would fit the given description
hemisphere
perabale
fwf
Semi Circle
hemisphere
A cylinder.