Question

The strain-stress plot for materials A, B, C and D is shown in the figure. Which material has the largest Young's modulus?
\includegraphics[width=0.5\linewidth]{Screenshot 2026-02-04 151551.png}

• A. A
• B. C
• C. B
• D. D

Hint:

Always look at the axes! In a Stress-Strain graph, steeper is stronger. In a Strain-Stress graph, flatter is stronger.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Young's Modulus (\(Y\)) is defined as the ratio of Stress to Strain (\(Y = \frac{\sigma}{\epsilon}\)). In a Stress-Strain graph, this is the slope of the linear region. However, this question provides a Strain-Stress plot (Strain on Y-axis, Stress on X-axis).
Step 2: Key Formula or Approach:
1. \(Y = \frac{\text{Stress}}{\text{Strain}}\).
2. On a Strain-Stress graph, \(\text{Slope} = \frac{\text{Strain}}{\text{Stress}} = \frac{1}{Y}\).
Step 3: Detailed Explanation:
Since \(Y = 1/\text{Slope}\), the material with the smallest slope (the line closest to the Stress/X-axis) will have the largest Young's Modulus.
- Material A has the least steep slope relative to the Stress axis. - Material D has the steepest slope relative to the Stress axis. Therefore, Material A is the stiffest and has the highest \(Y\).
Step 4: Final Answer:
(1) A.