If two solid-hemisphere s of same base radius r are joined together along their bases , then curved surface area of this new solid is
(a) (b) (c) (d)
Base radius of the hemisphere = r
Since the two hemispheres are joined end to end, it becomes a complete sphere.
Curved surface area of the new solid = total surface area of the sphere.
Hence, the correct answer is option (a).
RD Sharma (2016)