Question

The ratio of the stress to the strain within the elastic limit is called

• A. Modulus of Elasticity
• B. Poisson's ratio
• C. Plastic limit
• D. Yield point

Hint:

Remember that the Modulus of Elasticity ($E$) is a fundamental property used in material science and engineering to describe how much a material will deform under load before it starts to permanently change shape.

Answer 1

The Correct Option is A

Step 1: Understand the words.
Stress is the force acting on each unit of area inside a material. Strain is how much the material changes shape, given as a fraction of the original size.

Step 2: Write the meaning of each.
Stress is \[ \sigma = \frac{F}{A} \] and strain is \[ \epsilon = \frac{\Delta L}{L_0} \]

Step 3: Recall Hooke's law.
Within the elastic limit, stress is directly proportional to strain. \[ \sigma = E\,\epsilon \] The constant $E$ links the two.

Step 4: Name the constant.
The ratio of stress to strain is this constant $E$, which is called the Modulus of Elasticity. \[ E = \frac{\sigma}{\epsilon} \]

Step 5: Check the other choices.
Poisson's ratio compares sideways strain to lengthwise strain, not stress to strain. The plastic limit and the yield point are points on the curve where the material stops behaving elastically, not a ratio.

Step 6: State the answer.
So the ratio of stress to strain within the elastic limit is the Modulus of Elasticity. \[ \boxed{\text{Modulus of Elasticity}} \]