Question

Which of the following have both surfaces (flat and curved)? This question has multiple correct options.
A. Ball
B. An apple
C. Drum
D. Clock

Answer 1

Hint:In the above given question, we are given four different options. We have to determine which of these four given options are correct. We have to check whether the four given options have both kinds of surfaces or not, i.e. flat and curved surfaces. The triangular, square, and rectangular surfaces are known as the flat surfaces in nature. Whereas the spherical, conical and cylindrical surfaces are known as the curved surfaces in nature.

Complete step by step answer:
We are given four different options as, a ball, an apple, a drum and a clock. We have to determine whether each of these four given options have both flat and curved surfaces or not. In order to approach the solution, we will check each given option one by one, whether it has both surfaces or not.

A curved surface is that surface in which all the points that lie on the surface are equidistant from a point called as its centre.A ball is a completely spherical structure and does not have any other surface. Hence, it has only curved surfaces and no flat surface.

An apple has an irregular shape which does not fit in any category of surfaces. However the surface around an apple is partially curved but nowhere flat.

A drum has a cylindrical shape which is curved around its body and is also flat at the top and bottom. Hence, a drum has both flat and curved surfaces.

The shape of a clock varies and depends on the design of that clock. However, if we consider an ordinary round clock then it has a round shape at its boundaries i.e. is curved and the front side is a flat surface where the time is shown.

Hence, the drum and clock are the only correct options here.

Therefore the correct options are C and D.

Note:If we open any curved surface then we will get a flat surface and also if we roll a flat surface then we will get a curved surface. If the geometrical shapes have some curved surfaces and some flat surfaces, then we can find their surface area and volume for all this type of geometries such as cone, cylinder, sphere, etc.