10th Maths - Book Back Answers - Chapter 7 Unit - Excercise 7.5 - English Medium Guides

 

SSLC / 10th - Maths - Book Back Answers - Chapter 7 Unit Excercise 7.5 - English Medium

Tamil Nadu Board 10th Standard Maths - Chapter 7 Unit Exercise 7.5: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Chapter 7 Unit Exercise 7.5 – Maths from the Tamil Nadu State Board 10th Standard textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Chapter 7 Unit Exercise 7.5 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 10 students! Prepare well and aim for top scores. Thank you!

Chapter 7 Mensuration Unit Ex 7.5

1. The curved surface area of a right circular cone of height 15 cm and
base diameter 16 cm is
(A) 60π cm²
(B) 68π cm²
(C) 120π cm²
(D) 136π cm²
Answer Key:

(D) 136π cm²

  
2. If two solid hemispheres of same base radius r units are joined together along their bases, then curved surface area of this new solid is
(A) 4πr ² sq. units
(B) 6πr ² sq. units
(C) 3πr ² sq. units
(D) 8πr ² sq. units
Answer Key:

(A) 4πr ² sq. units

  
3. The height of a right circular cone whose radius is 5 cm and slant height is 13 cm will be
(A) 12 cm
(B) 10 cm
(C) 13 cm
(D) 5 cm
Answer Key:

(A) 12 cm

  
4. If the radius of the base of a right circular cylinder is halved keeping the same height, then the ratio of the volume of the cylinder thus obtained to the volume of original cylinder is
(A) 1:2
(B) 1:4
(C) 1:6
(D) 1:8
Answer Key:

(B) 1:4

  
5. The total surface area of a cylinder whose radius is 1/3 of its height is
(A) 9πh²/8 sq.units
(B) 24πh² sq.units
(C) 8πh²/9 sq.units
(D) 56πh²/9 sq.units
Answer Key:

(C) 8πh²/9 sq.units 

  
6. In a hollow cylinder, the sum of the external and internal radii is 14 cm and the width is 4 cm. If its height is 20 cm, the volume of the material in it is
(A) 5600π cm³
(B) 1120π cm³
(C) 56π cm³
(D) 3600π cm³
Answer Key:

(B) 1120π cm³ 

  
7. If the radius of the base of a cone is tripled and the height is doubled then the volume is
(A) made 6 times
(B) made 18 times
(C) made 12 times
(D) unchanged
Answer Key:

(B) made 18 times

  
8. The total surface area of a hemi-sphere is how much times the square of its radius.
(A) π
(B) 4π
(C) 3π
(D) 2π
Answer Key:

(C) 3π

  
9. A solid sphere of radius x cm is melted and cast into a shape of a solid cone of same radius. The height of the cone is
(A) 3x cm
(B) x cm
(C) 4x cm
(D) 2x cm
Answer Key:

(C) 4x cm

  
10. A frustum of a right circular cone is of height 16cm with radii of its ends as 8cm and 20cm. Then, the volume of the frustum is
(A) 3328π cm³
(B) 3228π cm³
(C) 3240π cm³
(D) 3340π cm³
Answer Key:

(A) 3328π cm³

  
11. A shuttle cock used for playing badminton has the shape of the combination of
(A) a cylinder and a sphere
(B) a hemisphere and a cone
(C) a sphere and a cone
(D) frustum of a cone and a hemisphere
Answer Key:

(D) frustum of a cone and a hemisphere

  
12. A spherical ball of radius r₁ units is melted to make 8 new identical balls each of radius r₂ units. Then r₁ : r₂ is
(A) 2:1
(B) 1:2
(C) 4:1
(D) 1:4

Answer Key:

(A) 2:1

  
13. The volume (in cm³) of the greatest sphere that can be cut off from a cylindrical log of wood of base radius 1 cm and height 5 cm is
(A) 4/3π
(B) 10/3π
(C) 5π
(D) 20/3π
Answer Key:
(A) 4/3π

 
14. The height and radius of the cone of which the frustum is a part are h₁ units and r₁ units respectively. Height of the frustum is h₂ units and radius of the smaller base is r₂ units. If h₂ : h₁ = 1 : 2 then r₂ : r₁ is
(A) 1 : 3
(B) 1 : 2
(C) 2 : 1
(D) 3 : 1

Answer Key:
(B) 1 : 2 

 
15. The ratio of the volumes of a cylinder, a cone and a sphere, if each has the same diameter and same height is
(A) 1:2:3
(B) 2:1:3
(C) 1:3:2
(D) 3:1:2

Answer Key:

(D) 3:1:2