Question

With rise in temperature, the Young's modulus of elasticity:

• A. Changes erratically
• B. Decreases
• C. Increases
• D. Remains unchanged

Hint:

Young's modulus decreases with temperature because increased thermal energy makes materials more ductile.

Answer 1

The Correct Option is B

Step 1: {Young's modulus definition} 
\[ Y = \frac{{Stress}}{{Strain}} \] 
Step 2: {Effect of temperature increase} : As temperature increases, strain increases, leading to a decrease in Young’s modulus.  
Thus, the correct answer is Young’s modulus decreases. 
 

Answer 2

Step 1: Young’s modulus \( Y \) is a measure of the stiffness of a material, defined as:
\( Y = \frac{\text{Stress}}{\text{Strain}} \)
It indicates how much a material resists deformation under tensile or compressive stress.

Step 2: When temperature increases, the atoms or molecules in a material vibrate more vigorously.
This leads to a reduction in interatomic forces and binding energy, making it easier to deform the material.

Step 3: As a result, for the same amount of stress, the material deforms more (i.e., strain increases).
This causes the ratio \( \frac{\text{Stress}}{\text{Strain}} \) — that is, Young’s modulus — to decrease.

Final Answer: Decreases