The stress-strain graphs for materials A and B are shown in Fig. 9.12.

The graphs are drawn to the same scale.

(a) Which of the materials has the greater Young’s modulus?

(b) Which of the two is the stronger material?

(a) From the graphs given in the question, we note that for a given strain, stress for A is more than that of B.

Hence, young’s modulus, which is defined as the ratio of tensile stress to tensile strain, is greater for A than that of B.

(b) Strength of a material is measured by the amount of stress required to cause fracture.

On observing the graphs mentioned in the question, we can see that material A is stronger than B since the stress curve in Graph for A fails at a larger distance compared to the curve in graph for B.