Question

The elastic region in a stress-strain diagram corresponds to:

• A. Plastic deformation
• B. Reversible deformation
• C. Necking
• D. Fracture

Hint:

In the elastic region, deformation is reversible — remove the load, and the material regains its original shape.

Answer 1

The Correct Option is B

The elastic region in a stress-strain curve is the initial linear portion where the material obeys Hooke’s law.
In this region, the material deforms under stress but returns to its original shape once the load is removed.
This is known as reversible deformation.
Once the stress exceeds the elastic limit or yield point, the material enters the plastic region, where deformations become permanent.
Incorrect options:
- (1) Plastic deformation occurs after the elastic limit.
- (3) Necking occurs in the plastic region just before fracture.
- (4) Fracture is the final failure point beyond the plastic region.