If ‘P’ is the tensile stress in a rectangular bar of length ‘L’ with ‘b’ and thickness ‘d’, the volumetric strain is given as

a) P ( 1 + 2 μ) / E

b) PL ( 1 – 2 μ) / bd

c) P ( 1 – 2 μ)

d) P ( 1 – 2 μ) / E (Ans)