An axially loaded member of length L and area of cross-section A is subjected to a tensile load of P. If E denotes the Young's modulus of elasticity, the strain energy stored in the member is equal to :
A(P²L)/2AE
B(PL²)/2AE
C(P²L)/AE
D(PL)/AE
A(P²L)/2AE
B(PL²)/2AE
C(P²L)/AE
D(PL)/AE