Question

Longitudinal strain is defined when ________.

• A. under a large force, change in length is smaller
• B. under a weak force, change in length be smaller
• C. under a large force, change in length is larger
• D. None of the above

Answer 1

The correct option is A under a large force, change in length is smaller

The Longitudinal stress is defined below the elastic limit, as the normal force per unit cross-section area.

$Stress=\frac{Force}{Area}$

i.e. the change in length or strain should be smaller, while the stress should be larger. $Strain=\frac{\Delta l}{l}$

Option A is correct.