# Elasticity - Long Question Answer | Physics Grade 11 Solution

### Long Question Solution

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#### Viva Voice Questions # Elasticity - Long Question Answer 3

Question: Explain Hooke’s law with the necessary figure and derive experimental verification of Hooke’s law.

Ans: Hooke’s law: It states that "stress acting on a given body is directly proportional to the strain within the elastic limit". So, mathematically we can write as
stres∝ strain
or, stress = E strain
therefore, stress/strain = E
Where E is the proportionality constant. Which is known as modulus of elasticity. Its value depends upon the nature of the materials. Its dimension formula is [ML-1T-2]. Experimental verification of Hooke’s law: The experimental set for the verification of Hooke’s law can be shown in the figure above. It consists of a vertical spring whose upper end be fixed with rigid support and its lower end be connected with weight. It also consists of a pointer (P) which slides on a fixed vertical scale to measure the extension of the spring.

At first, let the initial reading of a pointer on a vertical scale be noted when no weight be suspended on a spring. After this let some weight be placed on spring then final reading of a pointer on the vertical scale be noted. So that the difference between the final and initial reading of a pointer represents an extension of the spring. Let this process be repeated for increasing different weight on this we plot a graph between the extension of the spring along the y-axis and weight suspended on a spring along the x-axis. As shown in the figure below in which a straight line be obtained passing through origin which verifies the Hooke’s law. ## Popular Subjects

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