ML Aggarwal Solution Class 10 Chapter 17 Mensuration MCQs

 MCQs

Question 1

In a cylinder, if radius is halved and height is doubled then the volume will be

(a) same

(b) doubled

(c) halved

(d) four times

Sol :

Let radius of cylinder = r

and height = h

then volume = πr²h

If the radius is halved and the height is doubled

Then volume =π(r2)2×2h

=πr24×2h=12(πr2h)

which is half

Ans (c)


Question 2

In a cylinder, if the radius is doubled and height is halved then its curved surface area will be

(a) halved

(b) doubled

(c) same

(d) four times

Sol :

Let radius of a cylinder = r

and height = h

Then curved surface area = 2πrh

Now if radius is doubled and height is halved,

then curved surface area =2πr2×2h=2πrh which is same (c)


Question 3

If a well of diameter 8 m has been dug to the depth of 14 m, then the volume of the earth dug out is

(a) 352 m3

(b) 704 m3

(c) 1408 m3

(d) 2816 m3

Sol :

Diameter of a well = 8 m

Radius (r)=82=4m

Depth (h) = 14 m

Volume of the earth dug put = πr2h

=227×4×4×14 m3
=704 m3
Ans (b)


Question 4

If two cylinders of the same lateral surface have their radii in the ratio 4 : 9, then the ratio of their heights is

(a) 2 : 3

(b) 3 : 2

(c) 4 : 9

(d) 9 : 4

Sol :

Ratio in two cylinder having same lateral surface area their radii is 4 : 9

Let r1 be the radius of the first and r2 be the second cylinder

and h1,h2 and their heights

Let r1=4x and r2=9x

2πr1h1=2πr2h2

=2π4x×h1=2×π×9xh2

h1h2=9x4x=9:4

Ratio in their heights = 9 : 4 

Ans (d)


Question 5

The radii of two cylinders are in the ratio 2 : 3 and their heights are in the ratio 5 : 3. The ratio of their volumes is

(a) 10 : 17

(b) 20 : 27

(c) 17 : 27

(d) 20 : 37

Sol :

Radii of two cylinder are in the ratio = 2 : 3

Let radius (r1) = 2x

and radius (r2) = 3x

Ratio in their height = 5 : 3

Let height of the first cylinder = 5y

and of second = 3y

Now, volume of the first cylinder

πr21h=π(2x)2×5h=20πx2y

and volume of second =π(3x)2×3y

=π×27x2y

Ratio is 20πx2y:27πx2y

=20:27

Ans (b)


Question 6

The total surface area of a cone whose radius is r2 and slant height 2l is

(a) 2πr (l + r)

(b) πr(l+r4)

(c) πr(l + r)

(d) 2πrl

Sol :

Radius of a cone =r2

and slant height = 2l

total surface area of a cone

=πrl+πr2
=πr2×2l+π(r2)2
=πrl+πr24
=πr(l+r4)

Ans (b)

Question 7

If the diameter of the base of cone is 10 cm and its height is 12 cm, then its curved surface area is

(a) 60π cm2

(b) 65π cm2

(c) 90π cm2

(d) 120π cm2

Sol :

Diameter of the base of a cone = 10 cm

Radius (r)=102=5 cm

and height (h) = 12 cm

l=r2+h2=52+122
=25+144=169=13 cm

Curved surface area 

=πrl=π×5×13=65πcm2

Ans (b)


Question 8

If the diameter of the base of a cone is 12 cm and height is 20 cm, then its volume is ,

(a) 240π cm3

(b) 480π cm3

(c) 720π cm3

(d) 960π cm3

Sol :

Diameter of the base of a cone = 12 cm

Radius (r)=122=6 cm

and height (h) = 20 cm

Volume =13πr2h
=13π×6×6×20 cm3

=240πcm3

Ans (a)


Question 9

If the radius of a sphere is 2r, then its volume will be

(a) 43πr3
(b) 4πr3
(c) 8πr33
(d) 32πr33

Sol :

Radius of a sphere = 2r

Volume =43πr3=43π×(2r)3
=43π×8r3=32πr33
Ans (d)


Question 10

If the diameter of a sphere is 16 cm, then its surface area is

(a) 64π cm2

(b) 256π cm2

(c) 192π cm2

(d) 256 cm2

Sol :

Diameter of a sphere = 16 cm

Radius (r)=162=8 cm

Surface area =4π2=4π×8×8 cm2=256πcm2

Ans (b)


Question 11

If the radius of a hemisphere is 5 cm, then its volume is

(a) 2503πcm3
(b) 5003πcm3
(c) 75πcm3
(d) 1253πcm3
Sol :
Radius of a hemisphere (r) = 5 cm
Volume =23πr3=23π(5)3 cm3
=2503πcm3

Ans (a)

Question 12

If the ratio of the diameters of the two spheres is 3 : 5, then the ratio of their surface areas is

(a) 3 : 5

(b) 5 : 3

(c) 27 : 125

(d) 9 : 25

Sol :

Ratio in the diameters of two spheres = 3 : 5

Let radius of the first sphere = 3x cm

and radius of the second sphere = 5x cm

Ratio in their surface area

=4π(3x)2:4π(5x)2
9x2:25x2
=9: 25

Ans (d)


Question 13

The radius of a hemispherical balloon increases from 6 cm to 12 cm as air is being pumped into it. The ratio of the surface areas of the balloon in the two cases is

(a) 1 : 4

(b) 1 : 3

(c) 2 : 3

(d) 2 : 1

Sol :

Radius of balloon (hemispherical) in the original position = 6 cm

and in increased position = 12 cm

Ratio in their surface areas

4π(6)2:4π(12)2
=62:122=36:144
=1: 4
Ans (a)


Question 14

The shape of a Gilli, in the game of Gilli- danda, is a combination of






(a) two cylinders
(b) a cone and a cylinders
(c) two cones and a cylinder
(d) two cylinders and a cone
Sol :
The shape of a Gilli is the combination of
two cones and a cylinder (as shown in the figure). 
Ans (c)

Question 15

If two solid hemisphere of same base radius r are joined together along with their bases, then the curved surface of this new solid is
(a) 4πr2
(b) 6πr2
(c) 3πr2
(d) 8πr2
Sol :
Radius of two solid hemispheres = r
These are joined together along with the bases
Curved surface area =2π2×2=4πr2
Ans (a)

Question 16

During conversion of a solid from one shape to another, the volume of the new shape will
(a) increase
(b) decrease
(c) remain unaltered
(d) be doubled
Sol :
During the conversion of a solid into another, the volume of the new shaper will be the same.
i.e. remain unaltered
Ans (c)

Question 17

If a solid of one shape is converted to another, then the surface area of the new solid
(a) remains same
(b) increases
(c) decreases
(d) can’t say
Sol :
If a solid of one shape has conversed into another then
the surface area of the new solid will same or not same
i.e. can’t say.
Ans (d)

Question 18

If a marble of radius 2.1 cm is put into a cylindrical cup full of water of radius 5 cm and height 6 cm, then the volume of water that flows out of the cylindrical cup is
(a) 38.8 cm3
(b) 55.4 cm3
(c) 19.4 cm3
(d) 471.4 cm3
Sol :
Radius of a marble = 2.1 cm
Volume of marble =43πr3 cm3
=43×227×2.1×2.1×2.1 cm3
=38.88 cm3

Ans (a)

Question 19

The volume of the largest right circular cone that can be carved out from a cube of edge 4.2 cm is
(a) 9.7 cm3
(b) 77.6 cm3
(c) 58.2 cm3
(d) 19.4 cm3
Sol :
Edge of cube = 4.2 cm
Radius of largest cone cut out =42.22=2.1 cm
and height = 4.2 cm

Volume =13πr2h
=13×227×2.1×2.1×4.2 cm3
= 19.404
= 19.4 cm3
Ans (d)

Question 20

The volume of the greatest sphere cut off from a circular cylindrical wood of base radius 1 cm and height 6 cm is
(a) 288 π cm3

(b) 43πcm3

(c) 6 π cm3

(d) 4 π cm3

Sol :
Radius of cylinder (r) = 1 cm
Height (h) = 6 cm
The largest sphere that can be cut off from the cylinder of radius 1 cm

Volume =43πr3=43π(1)3
=43πcm3

Ans (b)

Question 21

The volumes of two spheres are in the ratio 64 : 27. The ratio of their surface areas is
(a) 3 : 4
(b) 4 : 3
(c) 9 : 16
(d) 16 : 9
Sol :
Ratio in volumes of two spheres = 64 : 27

Ratio in their radii =r31r32=6427

=(r1r2)3=(43)3

r1r2=43

Ratio in their surface area
=4πr214πr22=r21r22=(43)2=169

Ratio is 16: 9

Ans (d)


Question 22

If a cone, a hemisphere and a cylinder have equal bases and have same height, then the ratio of their volumes is

(a) 1 : 3 : 2

(b) 2 : 3 : 1

(c) 2 : 1 : 3

(d) 1 : 2 : 3

Sol :

If a cone, a hemisphere and a cylinder have equal bases = r (say)

and height = h in each case and r = h

Ratio in their volumes =13πr2h:23πr3:πr2h

=13πr2r:23πr3:πr2r

=13πr3:23πr3:πr3

=13:23:1=1:2:3

Ans (d)


Question 23

If a sphere and a cube have equal surface areas, then the ratio of the diameter of the sphere to the edge of the cube is

(a) 1 : 2

(b) 2 : 1

(c) √π : √6

(d) √6 : √π

Sol :

A sphere and a cube have equal surface area

Let a be the edge of a cube and r be the radius of the sphere, then

4πr2=6a2
π(2r)2:6a2(d=2r)
d2a2=6π
da=6π

Radii d:a=6:π

Ans (d)

Question 24

A solid piece of iron in the form of a cuboid of dimensions 49 cm x 33 cm x 24 cm is moulded to form a sphere. The radius of the sphere is

(a) 21 cm

(b) 23 cm

(c) 25 cm

(d) 19 cm

Sol :

Dimension of a cuboid = 49 cm × 33 cm × 24 cm

Volume of a cuboid = 49 × 33 × 24 cm3

⇒ Volume of sphere = Volume of a cuboid

Volume of a sphere = 49 × 33 × 24 cm3

Radius =( Volume 43π)13

=(49×33×24×3×74×22)13

=(49×7×3×3×3)13

=(7×7×7×3×3×3)13

=7×3=21 cm

Ans (a)


Question 25

If a solid right circular cone of height 24 cm and base radius 6 cm is melted and recast in the shape of a sphere, then the radius of the sphere is

(a) 4 cm

(b) 6 cm

(c) 8 cm

(d) 12 cm

Sol :

Height of a circular cone (h) = 24 cm

and radius (r) = 6 cm

Volume of a cone =13πr2h
=13π×6×6×24 cm3

Volume of sphere=Volume of a cone

Now volume of sphere =13π×36×24 cm3

Let r be in radius of sphere

Then 43πr3=13π×36×24

4r3=36×24r3=36×244

r3=3×3×3×2×2×2=33×23

r=3×2=6 cm

Ans (b)


Question 26

If a solid circular cylinder of iron whose diameter is 15 cm and height 10 cm is melted and recasted into a sphere, then the radius of the sphere is

(a) 15 cm

(b) 10 cm

(c) 7.5 cm

(d) 5 cm

Sol :

Diameter of a cylinder = 15 cm

Radius =152 cm

and height = 10 cm

Volume =πr2h=π×152×152×10 cm3

=1125π2 cm3

Volume of sphere =1125π2 cm3

Radius of sphere =( Volume 43π)13

=(1125π×32×4π)13=(33758)13

=(1125π×32×4π)13=(33758)13

333753112533755125525551

=(53×3323)13=5×32 cm

=152=7.5 cm

Ans (c)


Question 27

The number of balls of radius 1 cm that can be made from a sphere of radius 10 cm is

(a) 100

(b) 1000

(c) 10000

(d) 100000

Sol :

Radius of sphere (R) = 10 cm

Volume of sphere =43πR3=43π(10)3 cm3

=43π×1000 cm3

and radius of one ball (r)=1 cm

Volume of one ball =43π(1)3 cm3=43πcm3

Number of
4π×1000×33×4×π=1000
Ans (b)

Question 28

A metallic spherical shell of internal and external diameters 4 cm and 8 cm, respectively is melted and recast into the form of a cone of base diameter 8 cm. The height of the cone is
(a) 12 cm
(b) 14 cm
(c) 15 cm
(d) 18 cm
Sol :
The internal diameter of the metallic shell = 4 cm
and external diameter = 8 cm

Internal radius (r)=42=2 cm

Volume of metal used =43π(R3r3)
=43π(4323)cm3

=43×π(648)cm3

=43π×56 cm3

Diameter of cone =8 cm
Radius of cone =82=4 cm

Height = Volume 13πr2
=4π×56×33×1×π×4×4

=14 cm

Ans (b)


Question 29

A cubical ice cream brick of edge 22 cm is to be distributed among some children by filling ice cream cones of radius 2 cm and height 7 cm up to its brim. The number of children who will get the ice cream cones is
(a) 163
(b) 263
(c) 363
(d) 463
Sol :
Edge of a cubical icecream brick = 22 cm
Volume = a3=(22)3 = 10648 cm3
Radius (r) of ice cream cone (r) = 2 cm
and height (h) = 7 cm

Volume of one cone =13πr2h

=13×227×2×2×7 cm3=883 cm3
Number of cones =10648×388=363

Ans (c)

Question 30

Twelve solid spheres of the same size are made by melting a solid metallic cylinder of base diameter 2 cm and height 16 cm. The diameter of each sphere is
(a) 4 cm
(b) 3 cm
(b) 2 cm
(d) 6 cm
Sol :
Diameter of cylinder = 2 cm

Radius =22=1 cm

and height = 16 cm

Volume =πr2h

=227×1×1×16=3527 cm3

Volume of 12 solid spheres so formed

=3527 cm3

Volume of each sphere =3527×12=35284 cm3

Radius of each sphere =(352×3×784×4×22)13

=(1)13=1 cm

Diameter =2×1=2 cm

Ans (c)


Question 31

A hollow cube of internal edge 22 cm is filled with spherical marbles of diameter 0.5 cm and it is assumed that 18 space of the cube remains unfilled. Then the number of marbles that the cube can accommodate is

(a) 142296

(b) 142396

(c) 142496

(d) 142596

Sol :

Internal edge of a hollow cube = 22 cm

Volume =( side )3=(22)3=22×22×22 cm3=10648 cm3

Diameter of spherical marble =0.5 cm=12

Radius =12×12=14 cm

Volume =43πr3

=43×227×14×14×14 cm3

=11168 cm3

Space left unfilled =10648×18 cm3

=1331 cm3

Remaining volume for marbles

=106481331=9317 cm3

Number of marble to accommodate

=9317÷11168=9317×16811

=142296

Ans (a)


Question 32

In the given figure, the bottom of the glass has a hemispherical raised portion. If the glass is filled with orange juice, the quantity of juice which a person will get is

(a) 135 π cm3

(b) 117 π cm3

(c) 99 π cm3

(d) 36 π cm3

Sol :











Radius of base of cylinder (r) =62 cm=3 cm 

and height (h)= 15 cm

Volume of the glass =πr2h23πr3

=πr(rh23r2)

=π×3(3×1523×9)

=3π(456)cm3

=3π×39=117πcm3

Ans (b)

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