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9th Grade > Mathematics

SURFACE AREAS AND VOLUMES MCQs

Total Questions : 58 | Page 5 of 6 pages
Question 41.


A water container can hold 40 litres of water. Then the total number of ice cubes of side 5 cm which  the container can hold is ____.


  1.     480
  2.     200
  3.     320
  4.     280
 Discuss Question
Answer: Option C. -> 320
:
C

1 litre = 1000 cm3
40 litres = 40000 cm3


Volume of water in the container
=40 litres = 40000 cm3


Volume of each ice cube
=(Side)3
=53
=125 cm3


Number of ice cubes that can be fitted
=Volume of water containerVolume of each cube
=40000 cm3125 cm3
=320 ice cubes


Question 42.


In a circus, a motorcyclist performs his stunts inside a hollow sphere. The thickness of the sphere is negligible. If the diameter of the hollow sphere is 14 m, then find the area available for the motorcyclist to perform his stunts. 
(use π=227)


  1.     516 m2
  2.     616 m2
  3.     586 m2
  4.     486 m2
 Discuss Question
Answer: Option B. -> 616 m2
:
B

Radius of the sphere
=diameter2=142=7 m
 
Area available to the motorcyclist = Surface area of the sphere
=4πr2
=4×227×72

=616 m2
Hence, the available area to the motorcyclist is 616 m2.


Question 43.


A 3×3 Rubik's cube has a total surface area of 54 cm2. The area occupied by every single red tile of the cube is ___________ .


  1.     0.25 cm2
  2.     1 cm2
  3.     3 cm2
  4.     9 cm2
 Discuss Question
Answer: Option B. -> 1 cm2
:
B

Given,
Total surface area of the cube =54 cm2
We know that,
Cube has 6 number of faces.
Each face of the Rubik's cube contains 9 tiles.
Each Rubik's cube contains 9 red tiles.
 Area of each face 
=Total surface area of the cubeTotal number of faces of the cube=546=9 cm2


Now, area of each tile 
=Area of each faceTotal number of  tiles in each face=99=1 cm2
Hence, the area occupied by every single red tile of the cube is 1 cm2.


Question 44.


A juice seller fills juice into cylindrical glasses from a big cylindrical container of height 35.2 cm and radius 10 cm. He charges ₹10/- for a glass of height 10 cm and radius 4 cm. The amount he earns by selling the juice is ____.
(Use π=227)


  1.     ₹ 220/-
  2.     ₹ 110/- 
  3.     ₹ 170/-
  4.     ₹ 190/-
 Discuss Question
Answer: Option A. -> ₹ 220/-
:
A

We know that,
volume of a cylinder =πr2h
Number of glasses of juice that are sold
=volume of the vesselvolume of each glass=π×10×10×35.2π×4×4×10=22


 The amount earned by the shopkeeper
=Rate of each glass×Total number of glasses
=10×22= 220/


Question 45.


The volume of a cone of radius 7 cm and slant height 14 cm is ______.
(use π=227)


  1.     622.381 cm3
  2.     722.381 cm3
  3.     618.381 cm3
  4.     522.381 cm3
 Discuss Question
Answer: Option A. -> 622.381 cm3
:
A

Given,
Radius of the cone
 r=7 cm
Slant height of the cone
l=14 cm
The Volume Of A Cone Of Radius 7 Cm And Slant Height 14 Cm I...


From the pythagoras theorem
l2=h2 + r2,
height of the cone
h=14272
h=147=12.1243 cm


Volume of a Cone
=13×π ×r2h
=13×227×72×12.1243
=622.381 cm3


Question 46.


A hemispherical bowl fits exactly on the flat surface of a right circular cone whose height is 5 cm and radius is 3.5 cm. The volume of the solid formed is______.
A Hemispherical Bowl Fits Exactly On The Flat Surface Of A R...


  1.     144 cm3
  2.     132 cm3
  3.     154 cm3
  4.     169 cm3
 Discuss Question
Answer: Option C. -> 154 cm3
:
C

We know that,
volume of cone =13πr2h
volume of hemisphere =23πr3
Total volume
    = Volume of the cone + Volume of              the hemisphere


    =13πr2h+23πr3=13πr2(h+2r)=13×227×3.52×(5+7)=13×227×3.52×12=22×0.5×3.5×4=154 cm3
The volume of the solid formed is
    154 cm3      


Question 47.


Cuboids can be formed by stacking 


  1.     Rectangles
  2.     Squares
  3.     Triangles
  4.     Trapezium
 Discuss Question
Answer: Option A. -> Rectangles
:
A and B

Cuboids can be formed by stacking rectangles as shown in the figure.


Cuboids Can Be Formed By Stacking A   square can be defined as a rectangle in which the adjacent sides are equal. Thus, stacking squares also yields cuboids. In fact, we obtain a special type of cuboid in this case, called the cube.


Question 48.


Pavan drew a ABC right angled at B. He says if the right angle triangle is rotated along AB then it will result in ___ 


  1.     Cone
  2.     Cube
  3.     Cylinder
  4.     Cuboid
 Discuss Question
Answer: Option A. -> Cone
:
A

If right angle triangle is rotated along any of it's perpendicular side then we will get a right circular cone. See the image below
Pavan Drew A △ABC Right Angled At B. He Says If The Right ...


Question 49.


The cost of painting the curved surface area of a cylindrical pillar of height 10 m and radius 3.5 m at ₹ 10/- per sq. meter is ₹ 2200/-.
(use π=227)


  1.     True
  2.     False
 Discuss Question
Answer: Option A. -> True
:
A
Curved surface area of the cylindrical pillar
=2πrh
=2×227×3.5×10
=220 m2
So,
total cost of painting
=Curved Surface Area of pillar×Cost per m2
=220×10
= ₹ 2200/- 
Hence, the given statement is true.
Question 50.


The radius of a hemisphere having total surface area of 1848 sq. cm is 7 cm.


  1.     True
  2.     False
 Discuss Question
Answer: Option B. -> False
:
B
Total surface area =3πr2
3×227×r2=1848
r2=1848×73×22
r2=196
r=14 cm
Thus, above statement is false.

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