Surface Areas And Volumes CBSE Questions & Answers

Surface Areas And Volumes

This is Mathematics Class 09 Surface Areas and Volumes CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
If the volume of a sphere is 4851 \(c{m^3},\) then its surface area is
  • A
    2079 \(c{m^2},\)
  • B
    1386 \(c{m^2},\)
    Correct
  • C
    1039.5 \(c{m^2},\)
  • D
    693 \(c{m^2},\)
2
A hemispherical bowl is made of steel 0.25 cm thick. If the inner radius of the bowl is 3.25 cm, then the outer curved surface area of the bowl is
  • A
    38.5 \(c{m^2}.\)
  • B
    115.5 \(c{m^2}.\)
  • C
    154 \(c{m^2}.\)
  • D
    77 \(c{m^2}.\)
    Correct
3
If the surface area of a solid sphere is 1386 \(c{m^2}.\) then the total surface area of the solid hemisphere of the same radius is
  • A
    519.75 \(c{m^2}.\)
  • B
    1559.25 \(c{m^2}.\)
  • C
    693 \(c{m^2}.\)
  • D
    1039.5 \(c{m^2}.\)
    Correct
4
The number of spherical bullets each 5 dm in diameter which can be cast from a rectangular block of lead 11 m long, 10 m broad and 5 high is
  • A
    4200.
  • B
    5600.
  • C
    6300.
  • D
    8400.
    Correct
5
The number of solid sphere each 6 cm in diameter, which can be moulded from a solid cylinder of height 45 cm and diameter 4 cm without any loss is
  • A
    10
  • B
    12
  • C
    5
    Correct
  • D
    7
6
If a hollow sphere of internal and external diameters 4 cm and 8 cm respectively melted into a cone of base diameter 8 cm, then the height of the cone formed is
  • A
    14 cm.
    Correct
  • B
    12 cm.
  • C
    16 cm.
  • D
    8 cm.
7
If a sphere of radius 2r has the same volume as that of a cone with a circular base of radius r, then the height of the cone is
  • A
    30r.
  • B
    24r.
  • C
    28r.
  • D
    32r.
    Correct
8
If the radius and slant height of a cone are in the ratio 7 : 13 and its curved surface area is 286 \(c{m^2}.\) then its radius is
  • A
    7 cm.
    Correct
  • B
    10 cm.
  • C
    10.5 cm.
  • D
    7.5 cm.
9
The curved surface area of a right circular cylinder which just encloses a sphere of radius r is
  • A
    \(6\pi {r^2}.\)
  • B
    \(2\pi {r^2}.\)
  • C
    \(8\pi {r^2}.\)
  • D
    \(4\pi {r^2}.\)
    Correct
10
If a sphere is inscribed in a cube, then the ratio of the volume of the cube to the volume of the sphere is
  • A
    \(4:\pi .\)
  • B
    \(6:\pi .\)
    Correct
  • C
    \(\pi :4.\)
  • D
    \(\pi :6.\)
11
In a cylindrical drum of radius 4.2 m and height 3.5 m, the number of full bags of wheat can be emptied if the space required for wheat in each bag is 2.1 cu. M, is
  • A
    90
  • B
    92
    Correct
  • C
    91
  • D
    100
12
The curved surface of cylinder is 484 \(c{m^2}\) and height is 5.5 cm. Its radius is
  • A
    14 cm
    Correct
  • B
    21 cm
  • C
    7 cm
  • D
    14 m
13
A solid sphere of radius 3 cm is melted and then cast into small spherical balls, each os diameter 0.6 cm. The number of small balls so obtained is
  • A
    500
  • B
    1000
    Correct
  • C
    2000
  • D
    800
14
An icecream cone has hemispherical top. If the height of the cone is 9 cm and base radius is 2.5 cm, then the volume of icecream is
  • A
    91.67 \(c{m^3}\)
    Correct
  • B
    91.76 \(c{m^3}\)
  • C
    90.67 \(c{m^3}\)
  • D
    91.67 \(c{m^3}\)
15
The diameter of a sphere is 42 cm. It is melted and drawn into a cylindrical wire of diameter 2.8 cm. Then, the length of the wire is
  • A
    63 m
  • B
    126 cm
  • C
    6.3 cm
  • D
    63 cm
    Correct