# Physics Questions and Answers – Solids Mechanical Properties – Stress-Strain Curve

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This set of Physics Multiple Choice Questions & Answers (MCQs) focuses on “Solids Mechanical Properties – Stress-Strain Curve”.

1. Which of the following options is correct?

a) A – yield point, B – elastic limit, C – fracture point, D – Ultimate tensile strength
b) A – yield point, B – proportional limit, C – Ultimate tensile strength, D – fracture point
c) A – proportional limit, B – yield point, C – Ultimate tensile strength, D – fracture point
d) A – yield point, B – proportional limit, C – fracture point, D – Ultimate tensile strength

Explanation: The point A refers to the point till which hooke’s law can be followed, i.e: stress ∝ strain. It is also called the proportional limit. The point B refers to the point upto which if stress is applied the metal, on removal of stress, will regain its natural length. It is called yield point or elastic limit. The point C refers to the maximum tensile strength. And point D refers to the point where the material breaks or fractures.

2. A material have a stress strain curve which can look similar to the equation y = x2 (for all x>0). True or False?
a) True
b) False

Explanation: The stress strain curve of some elastic tissues of our bodies look similar to the curve represented by equation y = x2. For eg, the elastic tissue of aorta has a curve like:

3. The stress corresponding to fracture point is called ______
a) ultimate stress
b) breaking stress
c) yield stress
d) plastic stress

Explanation: Breaking stress refers to the stress at which the material fractures. Ultimate stress is the maximum stress a material can handle before breaking. The material doesn’t fracture at this stress. Yield stress refers to the stress after which plastic deformation begins.
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4. Which of the following statements is correct for ductile materials.
a) Large deformation takes place between elastic limit and fracture point
b) Have no proportional limit
c) Break immediately after proportional limit
d) Cannot be drawn into wires

Explanation: Ductile materials are those which can be drawn into wires as they deform by a significant amount between elastic limit and fracture point. The stress-strain curve of a ductile material looks like:

5. Which of the following statements is correct for brittle materials.
a) It breaks soon after elastic limit is crossed
b) It shows significant plastic deformation before breaking
c) It is used to make wires
d) Stress is never proportional to strain

Explanation: Brittle materials break soon after elastic limit. They show no significant plastic deformation and hence can’t be used for making wires. Their stress-strain curve looks like:

6. What does the area under the stress-strain curve represent?
a) Toughness
b) Total deformation
c) Modulus of elasticity
d) Average force applied

Explanation: Area under the stress-strain curves represents toughness. Total deformation is given by the net strain multiplied by original length. Modulus of elasticity is the ratio of stress to strain under elastic limit.

Sanfoundry Global Education & Learning Series – Physics – Class 11.