Exercise 13.2 Class 10 Maths NCERT Solutions PDF Download 2022
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Surface Areas and Volumes
Exercise 13.1 Introduction
Exercise 13.2 Surface Area of a Combination of Solids
Exercise 13.3 Volume of a Combination of Solids
Exercise 13.2 Class 10 Maths NCERT Solutions
Exercise 13.2 Class 10 Maths NCERT Solutions
Access Answers of Maths NCERT Class 10 Chapter 13 – Surface Areas and Volumes
NCERT solutions for class 10 maths chapter 13 Surface Areas and Volumes
Excercise: 13.2 Class 10 NCERT Solutions
Q.1 A solid is in the shape of a cone standing on a hemisphere with both their radii being equal to 1 cm and the height of the cone is equal to its radius. Find the volume of the solid in terms of .
Ans: (Exercise 13.1 Class 10) :-
The volume of the solid is given by :
The volume of solid = Volume of cone + Volume of a hemisphere
The volume of cone :
or
or
And the volume of the hemisphere :
or
or
Hence the volume of solid is :
Q.2 Rachel, an engineering student, was asked to make a model shaped like a cylinder with two cones attached at its two ends by using a thin aluminum sheet. The diameter of the model is 3 cm and its length is 12 cm. If each cone has a height of 2 cm, find the volume of air contained in the model that Rachel made. (Assume the outer and inner dimensions of the model to be nearly the same.)
Ans: (Exercise 13.1 Class 10) :-
The volume of air present = Volume of cylinder + 2 (Volume of a cone)
Now, the volume of a cylinder :
or
or
And the volume of a cone is :
or
or
Thus the volume of air is :
or
Q.3 A gulab jamun contains sugar syrup up to about 30% of its volume. Find approximately how much syrup would be found in 45 gulab jamuns, each shaped like a cylinder with two hemispherical ends with length 5 cm and diameter 2.8 cm (see Fig).
Ans: (Exercise 13.1 Class 10) :-
It is clear from the figure that gulab jamun has one cylindrical part and two hemispherical parts.
Thus, the volume of gulab jamun is = Volume of cylindrical part + 2 (Volume of the hemisphere )
Now, the volume of the cylinder is
or
or
And the volume of a hemisphere is :
Thus the volume of 1 gulab jamun is
Hence the volume of 45 gulab jamun
Further, it is given that one gulab jamun contains sugar syrup upto
So, the total volume of sugar present :
Q.4 A pen stand made of wood is in the shape of a cuboid with four conical depressions to hold pens. The dimensions of the cuboid are 15 cm by 10 cm by 3.5 cm. The radius of each of the depressions is 0.5 cm and the depth is 1.4 cm. Find the volume of wood in the entire stand (see Fig. 13.16).
Ans: (Exercise 13.1 Class 10) :-
The volume of wood is given by = volume of the cuboid – the volume of four cones.
Firstly, the volume of cuboid :
or
or
And, the volume of cone :
Thus the volume of wood is
Q.5 A vessel is in the form of an inverted cone. Its height is 8 cm and the radius of its top, which is open, is 5 cm. It is filled with water up to the brim. When lead shots, each of which is a sphere of radius 0.5 cm are dropped into the vessel, one-fourth of the water flows out. Find the number of lead shots dropped in the vessel.
Ans: (Exercise 13.1 Class 10) :-
According to the question :
Water spilled from the container = Volume of lead balls.
Let us assume the number of lead balls to be n.
Thus the equation becomes :
or
or
or
Hence the number of lead shots dropped is 100.
Q.6 A solid iron pole consists of a cylinder of height 220 cm and base diameter 24 cm, which is surmounted by another cylinder of height 60 cm and radius 8 cm. Find the mass of the pole, given that 1 cm 3 of iron has approximately 8g mass. (Use )
Ans: (Exercise 13.1 Class 10) :-
The pole can be divided into one large cylinder and one small cylinder.
Thus, the volume of pole = volume of large cylinder + volume of a small cylinder
or
or
or
or
Now, according to question mass of the pole is :
or
Q.7 A solid consisting of a right circular cone of height 120 cm and radius 60 cm standing on a hemisphere of radius 60 cm is placed upright in a right circular cylinder full of water such that it touches the bottom. Find the volume of water left in the cylinder, if the radius of the cylinder is 60 cm and its height is 180 cm.
Ans: (Exercise 13.1 Class 10) :-
It is clear from the question that the required volume is :
The volume of water (left) =Volume of a cylinder – Volume of solid
Now the volume of the cylinder is
or
And the volume of solid is :
Thus the volume of water left :
Q.8 A spherical glass vessel has a cylindrical neck 8 cm long, 2 cm in diameter; the diameter of the spherical part is 8.5 cm. By measuring the amount of water it holds, a child finds its volume to be 345 cm 3 . Check whether she is correct, taking the above as the inside measurements, and .
Ans: (Exercise 13.1 Class 10) :-
The volume of the vessel is given by :
The volume of vessel = Volume of sphere + Volume of the cylindrical part
Now, the volume of the sphere is :
And the volume of the cylinder is:-
Thus the volume of the vessel is
More About NCERT Solutions for Class 10th Maths Exercise 13.2:-
NCERT Solutions for Class 10th Maths exercise 13.2- The most important part of NCERT Solutions for Class 10th Maths chapter 13 Exercise 13.2 is that it helps you to determine how to break the figure in those parts or shapes with which we are familiar and we know their formulas. For example – In the question given in number 2 of exercise 13.2, we have broken the shape using two cones and one cylinder because we are familiar with these shapes. We should also know different formulas like formulas for finding the volume of cones, cylinders etc.
Some important formulas are:
Volume of cube =
Volume of cylinder
Benefits of NCERT Solutions for Class 10 Maths Exercise 13.2
-
Exercise 13.2 Class 10 Maths, is based on Volume of a Combination of Solids.
-
Class 10 maths chapter 13 exercise 13.2 helps us in understanding complex shapes and finding its volume.
-
Class 10th maths chapter 13 exercise 13.2 helps us to simplify complex shapes by breaking it into smaller individual objects that are simple to our understanding.
Frequently Asked Question (FAQs) – NCERT Solutions for Exercise 13.2 Class 10 Maths Chapter 13 – Surface Area and Volumes
Q:-What is the core concept of NCERT solutions for class 10 maths exercise 13.2?
Ans: (Exercise 13.1 Class 10) :-
The core concept behind this exercise is to find the volume combination of solids. We have to remember the formula for finding the volume of cuboid, sphere, cylinder etc
Q:- Write the formula for finding the volume of cone, cylinder and sphere?
Ans: (Exercise 13.1 Class 10) :-
Cone
Cylinder
Sphere
Q:-If a cone and a hemisphere of same radius are placed on one another such that the hemisphere lies in the bottom of the arrangement, find the total volume of the arrangement?
Ans: (Exercise 13.1 Class 10) :-
Total volume = volume of cone + volume of hemisphere
Total volume
(Where is the r radius of the cone and h is the height of the cone)
Q:-If a cylinder and a hemisphere of same radius are placed on one another such that the cylinder lies in the bottom of the arrangement, find the total volume of the arrangement?
Ans: (Exercise 13.1 Class 10) :-
Total volume = volume of cylinder + volume of hemisphere
Total volume
(Where is the r radius of the cylinder and h is the height of the cylinder)
Q:- How many cubes of side ‘x’ is required to make a new cube of side ‘2x’?
Ans: (Exercise 13.1 Class 10) :-
Our initial volume is
Out final volume is
No of cubes required
Q:- A cube of ‘x’ is placed below a sphere such that the diameter of the sphere is equal to the diagonal of the face of the cube. Find the total volume of the arrangement?
Ans: (Exercise 13.1 Class 10) :-
Since the diameter is equal to the diagonal of the face of the cube
So, the radius is
Where is the
diagonal of the cube and r is the radius of the sphere
Now we replace the radius of the sphere by
Total volume
Total volume
Q:-A hemisphere is removed from the bottom of a cylinder of radius ‘r’ and height ‘3r’ find the volume of the remaining portion?
Ans: (Exercise 13.1 Class 10) :-
Total volume = volume of the cylinder – the volume of the hemisphere
Volume of cylinder
Volume of hemisphere
Total volume
Now h=3r
Total volume
EXERCISE 13.2
1 . A solid is in the shape of a cone standing on a hemisphere with both their radii being
equal to 1 cm and the height of the cone is equal to its radius. Find the volume of the solid
in terms of π.
2. Rachel, an engineering student, was asked to make a model shaped like a cylinder with
two cones attached at its two ends by using a thin aluminium sheet. The diameter of the
model is 3 cm and its length is 12 cm. If each cone has a height of 2 cm, find the volume
of air contained in the model that Rachel made. (Assume the outer and inner dimensions
of the model to be nearly the same.)
3. A gulab jamun, contains sugar syrup up to about
30% of its volume. Find approximately how much
syrup would be found in 45 gulab jamuns, each
shaped like a cylinder with two hemispherical ends
4. A pen stand made of wood is in the shape of a
cuboid with four conical depressions to hold pens.
The dimensions of the cuboid are 15 cm by 10 cm by
3.5 cm. The radius of each of the depressions is 0.5
cm and the depth is 1.4 cm. Find the volume of
wood in the entire stand (see Fig. 13.16).
5. A vessel is in the form of an inverted cone. Its
height is 8 cm and the radius of its top, which is
open, is 5 cm. It is filled with water up to the brim.
When lead shots, each of which is a sphere of radius
0.5 cm are dropped into the vessel, one-fourth of
the water flows out. Find the number of lead shots
dropped in the vessel.
6. A solid iron pole consists of a cylinder of height 220 cm and base diameter 24 cm, which
is surmounted by another cylinder of height 60 cm and radius 8 cm. Find the mass of the
pole, given that 1 cm3 of iron has approximately 8g mass. (Use π = 3.14)
7. A solid consisting of a right circular cone of height 120 cm and radius 60 cm standing on
a hemisphere of radius 60 cm is placed upright in a right circular cylinder full of water
such that it touches the bottom. Find the volume of water left in the cylinder, if the radius
of the cylinder is 60 cm and its height is 180 cm.
8. A spherical glass vessel has a cylindrical neck 8 cm long, 2 cm in diameter; the diameter
of the spherical part is 8.5 cm. By measuring the amount of water it holds, a child finds its
volume to be 345 cm3.
Exercise 13.2 Class 10 Maths NCERT Solutions PDF Download 2022
Exercise 13.2 Class 10 Maths NCERT Solutions PDF Download 2022
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