Question

Assertion :The linear portion of the stress-strain curve is the elastic region and the slope is the modulus of elasticity or Young's Modulus. Reason: Young's Modulus is the ratio of the compressive stress to the longitudinal strain.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

From hook's law.

We know,

$\frac{stress}{strain}=constant$

So, strss-strain graph will be a straight line.

Also,

$\frac{stress}{strain}=coefficientofelasticity$

$\therefore$ the slope of the graph will give coefficient of elasticity where $A$ is the elastic limit.

Young modulus is a coefficient of elasticity and it is defined as,

$Y=\frac{Stress}{Longitudinalstrain}$

$Y$ is being calculated if a metal wire streched on compressed.So, strain will be longitudinal.