PL³/3EI is the deflection under the load P of a cantilever beam. What will be the strain energy?

A)
P²L³/3EI
B)
P²L³/6EI
C)
P²L³/4EI
D)
P²L³/24EI

Correct Answer :   P²L³/6EI


Explanation : We may do it taking average

Strain energy = Average force x displacement = (P/2) x PL³/3EI = P²L³/6EI.