Sir, Please help me with this problem. # A wire of cross sectional area a, length L and young’s modulus Y is extended by an external force F. What is the total energy stored in the wire? I solved it in the following way: Energy stored = ½ x stress x strain = (½) x (F/a) x (dL/L) = (½) x (F/a) x (F/aY) = (1/2) x (F^2/a^2Y) Is it right? But the answer given in my book is ½(YF^2L/a). Here the symbol ^ represents power and x represents multiplication.