Question

Modulus of elasticity is a measure of

• A. True stress
• B. Toughness
• C. Stiffness
• D. Resilience

Hint:

Associate these key concepts:

• Modulus of Elasticity \(\rightarrow\) Stiffness (Resistance to elastic deformation)

• Area under elastic curve \(\rightarrow\) Resilience (Elastic energy storage)

• Area under total curve \(\rightarrow\) Toughness (Energy absorption before fracture)

Answer 1

The Correct Option is C

Step 1: Recall the physical meaning of Young's modulus.
Within the elastic region, Hooke's law says $\sigma = E\epsilon$, so $E = \dfrac{\sigma}{\epsilon}$ tells you how much stress you need to produce a given elastic strain.
Step 2: Think about what a large or small value of E means in practice.
A material with a high E, like steel, barely stretches even under a large stress, it strongly resists elastic deformation. A material with a low E, like rubber, stretches a lot for very little stress, it deforms easily. This everyday resistance to being stretched or bent elastically is exactly what engineers call stiffness.
Step 3: Distinguish it from the other options.
Toughness is about energy absorbed up to fracture, resilience is about elastic energy stored up to the yield point, and true stress is just a way of computing stress, none of these describe the slope of the elastic line the way stiffness does, so Young's modulus is properly understood as the measure of stiffness.
\[ \boxed{\text{Stiffness}} \]