Observation

In 2(a), most candidates accurately defined strain energy.
             A few of the candidates mistook strain energy for elastic constant.
             In 2(b), some candidates rendered the expression as instead of .
           
 EXPECTED RESPONSES:

        (a)        Definition of strain energy
The energy stored in a material as a result of a change in its shape/size/dimension.
OR
The potential energy stored in an object when it is deformed/ stretched/compressed by an applied force.
OR
The work done on a material when a force is applied to change its shape/stretch it/compress it.

(b)        Expression for E in terms of l, A, e and Y