Q.

An aluminium rod with Young's modulus Y=7.0×1010 N/m2 undergoes elastic strain of 0.04%. The energy per unit volume stored in the rod in SI unit is     [2023]

1 11200  
2 2800  
3 5600  
4 8400  

Ans.

(3)

Y=7×1010 N/m2

Strain=0.04100

Energy=12(YA)(Δx)2

Energy=12YA(Δx)2×

EV=12×Y×strain2=12×7×1010×0.04×0.04104=56×102