16.The ratio of direct stress to volumetric strain in case of a body subjected to three mutually perpendicular stresses of equal intensity, is equal to

17.For which material the Poisson's ratio is more than unity

18.The stress necessary to initiate yielding is

19.In question 56, the internal reaction in bottom 80 cm length will be

20.The stress at which extension of the material takes place more quickly as com�pared to the increase in load is called