What is Poisson’s Ratio?

Question

Question

It is the ratio of lateral strain to longitudinal strain
It is the ratio of force to the area
It is the ratio of change in radius or diameter to the original radius or diameter
It is the ratio of change in length to the original length

Answer 1

CONCEPT:

When a long bar is stretched by a force along its length than its length increases and the radius decreases.

Lateral strain: The ratio of change in radius or diameter to the original radius or diameter is called lateral strain.
Longitudinal strain: The ratio of change in length to the original length is called longitudinal strain.

EXPLANATION:

Poisson's ratio: The ratio of lateral strain to longitudinal strain is called Poisson’s ratio (σ). Therefore option 1 is correct.

The negative sign indicates that the radius of the bar decreases when it is stretched.
Poisson’s ratio is a dimensionless and a unitless quantity.
The ratio of force to the area is pressure. Therefore option 2 is incorrect.
The ratio of change in radius or diameter to the original radius or diameter is called lateral strain. Therefore option 3 is incorrect.
The ratio of change in length to the original length is called longitudinal strain. Therefore option 4 is incorrect.