Question

The stress-strain graphs for materials A and B are shown in Fig. 9.12. The graphs are drawn to the same scale: Which of the materials has the greater Young's modulus?

Answer 1

Hello Buddy !!

Well we know that Young' modulus = Stress/Strain

While refering with respect to the graph here there is a simple trick

Since Young's modulus is stress by strain and the graph given is stress vs strain

The slope of the line would give the magnitude of Young's modulus

And note Young's from graph is valid upto only till elastic limit that somewhere where the straight line graph ends ... so whatever is followed as a straight line comes under elastic limit and thus elastic constant are valid over there (This can be understood by Hooke's law )

Thus the slope of straight line in figure 1 > slope of straight line in figure 2

Hence material corresponding to graph 1 has greater Young's modulus than that of graph 2

Hope this helps !! ^_^