It could be a semi-sphere but mostly it's a cone.
a cylinder
A circle
A cone. It has a circle for the base, and a curved face tapering to a point.
a circle
A plane circular face and a curved shape which, if flattened out would be a sector of a circle.A plane circular face and a curved shape which, if flattened out would be a sector of a circle.A plane circular face and a curved shape which, if flattened out would be a sector of a circle.A plane circular face and a curved shape which, if flattened out would be a sector of a circle.
Semi Circle
The answer is - a cone.
a cone
The shape you are describing is a cylinder. A cylinder has two circular faces, which are also known as bases, and one rectangular face, which is called the lateral face. The lateral face of a cylinder is formed by unrolling the curved surface of the cylinder into a flat shape, creating a rectangle.
A figure that has a curved face or curved edge.
Tricky question, because you said 'one face'. A face is usually associated with a three-dimensional object, and a side is usually associated with a two-dimensional object. However, I think I know what you're getting at: It could appear to be a sphere (three dimensional). It is a circle (two dimensional). Keep in mind, that spheres technically have an infinite number of faces (not one), but it's deceiving because you can't see the individual faces of a sphere as they are infinitesimally small and the mind wants to think of it as having only one face since a sphere looks exactly the same no matter what angle you're viewing it from. A circle has one face, of course -- but infinite _sides_. How does that answer your question?
a circle has no face a sphere on the other hand does