Question

The stress strain graphs for two materials $A$ and $B$ are shown in figure. The graphs are drawn to the same scale. Select the correct statement.

• A. Material $A$ has greater Young's Modulus
• B. Material $A$ is more ductile
• C. Material $B$ is more ductile
• D. Both (a) and (b)

Answer 1

The correct option is D Both (a) and (b)


Slope of stress-strain curve $\left(\tan \theta \right)$ gives the value of Young's modulus for given material.
$\Rightarrow \tan \theta =$ Young's modulus $\left(Y\right)$
And from the graph we can clearly see,
${\theta }_A>{\theta }_B$
$\Rightarrow \tan {\theta }_A>\tan {\theta }_B$
So, material $A$ has greater Young's modulus.
Again, $P$ to $Q$ length in material $A$ is greater than $P$ to $Q$ length in material $B$. Which implies more deformation is possible in $A$ as compared to $B$.
Hence, we can say $A$ is more ductile than $B$.