Question

The stress-strain curves for brass, steel and rubber are shown in the figure. The lines A, B and C are for
     
(A) Rubber, brass and steel respectively
(B) Brass, steel and rubber respectively
(C) Steel, brass and rubber respectively
(D) Steel, rubber and brass respectively

Answer 1

Hint The slope of the stress-strain graph gives us the Young’s Modulus of elasticity . More the slope of the graph, more will be the value of Young’s Modulus of elasticity , more will be the elastic material .

Complete Step-by-step Solution
To identify which line belongs to which material , we will first learn about stress-strain diagrams in detail.
The graph that is given to us is –
     
The stress diagram can be drawn for any material. It tells us whether the substance is elastic or not. In simpler terms it tells us about the elasticity of any substance. The slope of different materials is different. Different materials can have very different values of slope. The ratio of stress to that of strain is called Young’s modulus. The slope of the graph gives us the value of Young’s modulus.
We are given three materials- steel, brass and rubber. Out of the three steel is the most elastic, rubber the least while the elasticity of brass lies in between the two.
 Out of the three lines given in the curve. A has the maximum slope, C the minimum slope. And B in between . The Young’s Modulus for A is maximum making it the most elastic , C the least elastic and B in between.
We can draw the parallels in between the three-
A-maximum slope-most elastic-steel
B-moderate slope-medium elasticity- brass
C-minimum slope-least elastic-rubber

Hence, the correct option is C .

Note Young’s Modulus is a property of material. The area of the graph also helps us differentiate between brittle and ductile material.