Question

Which of the following stresses causes change in density, as long as force acts on the body?

(a) Shear stress

(b) Compressive Stress

(c) Tensile stress

(d) Volumetric stress

The question was asked in quiz.

This interesting question is from Solids Mechanical Properties topic in chapter Mechanical Properties of Solids of Physics – Class 11

Answer 1

Right option is (d) Volumetric stress

For explanation: Volumetric stress is due to forces applied on the surface of a body from all directions such force is along normal at each point. This causes a change in volume while mass, obviously, remains the same. So, there is a slight change in density. Note that it is negligible but this change of density doesn’t occur in any other type of stresses, as the change in longitudinal length is compensated by change in lateral length in case of longitudinal stresses.