The basic difference between stress and strain is that stress is the deforming force per unit area, While strain is the apparent change in the shape, volume, or length of an object caused due to stress is called strain. The strain has no unit.
What is Stress?
It is defined as the force applied to the unit area to produce a change in the shape, volume, or length of a body. Mathematically it is expressed as:
The SI unit of stress (σ) is a newton per square meter (Nm^{2}), which is given the name pascal (pa).
Types of stress
Stress may cause a change in length, volume, and shape.

Tensile stress
When stress changes the length, it is called tensile stress.

Compressional stress
When stress changes its volume, it is called compressional stress.

Shear stress
When stress changes the shape, it is called shear stress.
What is Strain?
The strain is a measure of the deformation of a solid when stress is applied to it. In the case of deformation in onedimensional strain is defined as the fractional change in length. If Δl is the change in length and l is the original length, then strain is given by:
Types of strain
Since strain is the ratio of lengths, it is dimensionless, and therefore, has no units.
Tensile strain
If the strain is ε is due to tensile stress σ, it is called tensile strain.
Compressive strain
If the strain is produced as a result of compressive stress, it is called compressive strain.
Volumetric strain
When the applied stress changes the volume, the change in volume per unit volume is known as volumetric strain.
Shear strain
When the opposite faces of a rigid cube are subjected to shear stress.
Stress Vs Strain
Stress  Strain 
Stress is the restoring or deforming force per unit area.  The strain is the change in shape per the original shape. 
Its formula is σ = F/A  Its formula is ∈ = ΔL/L 
Its unit is N/m²  It has no unit 
Relation between stress and strain
For Related Topics visit our page: Mechanics
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I was able to understand the explanation without stress
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