NCERT Mathematics Class 9 Exemplar Ch 13 Surface Areas and Volumes Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Exercise 13.2

Q. 1. The volume of a sphere is equal to two-third of the volume of a cylinder whose height and diameter are equal to the diameter of the sphere.

Q. 2. If the radius of a right circular cone is halved and height is doubled, the volume will remain unchanged.

Answer: False, since new volume = (Original volume)

Q. 3. In a right circular cone, height, radius and slant height do not always be sides of a right triangle.

Q. 4. If the radius of a cylinder is doubled and its curved surface area is not changed, the height must be halved.

Q. 5. The volume of the largest right circular cone that can be fitted in a cube whose edge is 2r equals to the volume of a hemisphere of radius r.

Answer: True, since volume of cone = volume of hemisphere

Q. 6. A cylinder and a right circular cone are having the same base and same height. The volume of the cylinder is three times the volume of the cone.

Q. 7. A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is 1: 2: 3.

Q. 8. If the length of the diagonal of a cube is 6 3 cm, then the length of the edge of the cube is 3 cm.