NCERT Solutions for Class 11 Physics, Chapter 9 - Mechanical Properties of Solids

Stressing upon the importance of physical and mechanical properties of a solid substance will be simply an understatement. The very roots of mechanical and civil engineering are the two foundational engineering subjects that are required for understanding these properties. There is a specialised subject for college-level studies for the strength of materials. Chapter 8 of the book, Physics Part-II, consists of the 7 sub-sections, where each section explains the various aspects of the chapter, it comprises of a small part of the enormous subject matter.

Let us take a look at the subtopics of Class 11 Physics, Chapter 9, Mechanical Properties of Solids. 

9.1. Introduction.

9.2. Elastic Behavior of Solids.

9.3. Stress and Strain.

9.4. Hooke’s Law.

9.5. Stress-Strain Curve.

9.6. Elastic Moduli.

       9.6.1. Young’s Modulus

       9.6.2. Shear Modulus

       9.6.3. Bulk Modulus.

       9.6.4. Poisson’s Ratio.

       9.6.5. Elastic Potential Energy in a Stretched Wire.

9.7. Applications of Elastic Behavior of materials.

In class 11 Physics, Chapter 9, you will learn:

Section 9.1: In this section, you will learn that the heading indicates, the introduction prepares the student by providing relevant information about the basics needed to understand this chapter. The terms elasticity, plasticity, deformation are briefly explained, along with suitable examples.

Section 9.2: In this section, you will learn about the way the structure of a solid is affected at a molecular level under the effect of deformation due to stress. You will also read about Robert Hooke, the English physicist whose experiments on springs attached with load and weights gave us fundamental laws in the context of understanding stress and strain.

Section 9.3: In this section, you will learn many terms of physics, stress is the resisting force per unit area offered by a body when a deforming force acts upon it. Its units of measurement are the same as Pressure. Stress can be further categorised, depending upon its nature into Longitudinal Stress and Shearing Stress. The elongation formed due to stress is called strain. We shall learn in detail on this topic.

Section 9.4: In this section, you will learn what is according to Hooke’s law, stress and strain are proportional to each other for small deformations. The constant of proportionality is known as the Young’s Modulus. An experimentally obtained law, Hooke’s law is observed to be valid in most cases. However, there are substances in nature that do not obey Hooke’s Law.

Section 9.5: In this section, you will learn about the graphical representation of stress and strain. We shall also learn new terms like yield strength, ultimate stress, fracture point, etc. it is essential to know these details, especially for cases relating to safety and failing factors. For more information, you can refer to Mechanical Properties of Solids Class 11 Questions and Answers Pdf.

Section 9.6: In this section, you will learn that an elastic modulus (also known as the modulus of elasticity) is the measurement of an object’s resistance to deformation due to stress. There are three types of Modulus, namely Young’s Modulus, Shearing Modulus and Bulk (Volumetric) Modulus. The topic also includes Poisson’s Ratio, which is the ratio between Lateral Strain and Longitudinal Strain. More details are discussed in the chapter.

Section 9.7: In this section, you will learn about stress and strain conditions under different situations such as loading at the centre, and their applications.

At UrbanPro, we provide you with Mechanical Properties of Solids Class 11 NCERT Solutions for you to refer to, for your next examination.