# NCERT Mathematics Class 10 Exemplar Ch 12 Surface Areas and Volumes Part 3

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**EXERCISE 12.2**

1. Two identical solid hemispheres of equal base radius are stuck together along their bases. The total surface area of the combination is .

Answer: False

2. A solid cylinder of radius r and height h is placed over other cylinder of same height and radius. The total surface area of the shape so formed is .

Answer: False

3. A solid cone of radius r and height h is placed over a solid cylinder having same base radius and height as that of a cone. The total surface area of the combined solid is

Answer: False

4. A solid ball is exactly fitted inside the cubical box of side a. The volume of the ball is .

Answer: False

5. The volume of the frustum of a cone is , where h is vertical height of the frustum and are the radii of the ends.

Answer: False

6. The capacity of a cylindrical vessel with a hemispherical portion raised upward at the bottom as shown in the Fig. 12.7 is .

Answer: True

7. The curved surface area of a frustum of a cone is , where , and are the radii of the two ends of the frustum and h is the vertical height.

Answer: False

8. An open metallic bucket is in the shape of a frustum of a cone, mounted on a hollow cylindrical base made of the same metallic sheet. The surface area of the metallic sheet used is equal to curved surface area of frustum of a cone + area of circular base + curved surface area of cylinder

Answer: True