NCERT Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8.
- Surface Areas and Volumes Class 9 Ex 13.1
- Surface Areas and Volumes Class 9 Ex 13.2
- Surface Areas and Volumes Class 9 Ex 13.3
- Surface Areas and Volumes Class 9 Ex 13.4
- Surface Areas and Volumes Class 9 Ex 13.5
- Surface Areas and Volumes Class 9 Ex 13.6
- Surface Areas and Volumes Class 9 Ex 13.7
- Surface Areas and Volumes Class 9 Ex 13.8
- Surface Areas and Volumes Class 9 Ex 13.9
| Board | CBSE |
| Textbook | NCERT |
| Class | Class 9 |
| Subject | Maths |
| Chapter | Chapter 13 |
| Chapter Name | Surface Areas and Volumes |
| Exercise | Ex 13.8 |
| Number of Questions Solved | 10 |
| Category | NCERT Solutions |
NCERT Solutions for Class 9 Maths Chapter 13 Surface Areas and Volumes Ex 13.8
Assume π = \(\cfrac { 22 }{ 7 } \) unless stated otherwise.
Ex 13.8 Class 9 Maths Question 1.
Find the volume of a sphere whose radius is
(i) 7 cm
(ii) 0.63 m
Solution.
(i) We have, r = 7 cm
Ex 13.8 Class 9 Maths Question 2.
Find the amount of water displaced by a solid spherical ball of diameter.
(i) 28 cm
(ii) 0. 21
Solution.
Ex 13.8 Class 9 Maths Question 3.
The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3?
Solution.
Ex 13.8 Class 9 Maths Question 4.
The diameter of the Moon is approximately one-fourth of the diameter of the Earth. What fraction of the volume of the Earth is the volume of the Moon?
Solution.
Let diameter of the Earth be d2.
According to the question,
Ex 13.8 Class 9 Maths Question 5.
How many liters of milk can a hemispherical bowl of diameter 10 cm hold?
Solution.
Ex 13.8 Class 9 Maths Question 6.
A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank.
Solution.
Ex 13.8 Class 9 Maths Question 7.
Find the volume of a sphere whose surface area is 154 cm2.
Solution.
Ex 13.8 Class 9 Maths Question 8.
A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of Rs. 498.96. If the cost of white-washing is Rs. 2.00 per sq m, then find the
(i) inside surface area of the dome,
(ii) volume of the air inside the dome.
Solution.
Given, Cost of white – Washed = Rs. 498.96
and cost of whitewashed per sq.m = Rs. 2.00
Ex 13.8 Class 9 Maths Question 9.
Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S’. Find the
(i) radius r’ of the new sphere,
(ii) ratio of S and S’.
Solution.
Ex 13.8 Class 9 Maths Question 10.
A capsule of medicine is in the shape of a sphere of diameter 3.3. How much medicine (in mm3) is needed to fill this capsule?
Solution.
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