The amount of deformation experienced by an object under stress, divided by its initial dimensions, is called strain. Strain is a dimensionless quantity. If the deformation due to the applied force results in an increase in the length of an object, it is called tensile strain. Whereas, if the length decreases due to stress, it is called compressive strain. The change in the volume of an object due to the applied force in all directions is known as bulk strain. If the direction of the force is parallel to the object's plane, it undergoes deformation along that plane, and this is known as shear strain. For small deformations, the elastic modulus is defined as the ratio of the stress exerted on the object to the resultant strain. Young's modulus is the ratio of tensile stress to tensile strain. The ratio of volumetric stress to volumetric strain is known as bulk modulus, whereas the ratio of shear stress to shear strain corresponds to shear modulus.