The ratio of shear stress to the corresponding shear strain with in the elastic limit is known as ____.

I. Modulus of rigidity

II. Shear modulus 

Explanation:

Poisson’s ratio (μ) 

The ratio of lateral strain to the longitudinal strain for a given material, when the material is stressed within the elastic limit is its Poisson's ratio.

\(\rm{\mu = \frac{{Transverse\;strain}}{{Longitudinal \;strain}}}\)

Bulk Modulus of Elasticity 

It is defined as the ratio of compressive to the volumetric strain of the body.

\(\rm{K\;\left( {{{Bulk}}\;{{Modulus}}\;{{of}}\;{{Elasticity}}} \right) = - \frac{{dP}}{{\left( {\frac{{dV}}{V}} \right)}}}\)

Modulus of Rigidity 

It is also known as Shear Modulus is defined as the ratio of shear stress to shear strain.

\(\rm{∴ G\left( {{{Modulus}}\;{{of}}\;{{Rigidity}}} \right) = \frac{{Shear\;stress}}{{Shear\;strain}} = \frac{\tau }{\phi }}\)