The (a) part of this question was on definition of terms related to the elastic properties of matter. It was quite popular among the candidates. The candidates perform fairly well. The numerical part was poorly attempted. Because of conversion of units and simple arithmetic processes.
The expected answers are:
Force constant = the push/pull/ of force that causes a unit extension (of an elastic material)
(b) E = ½ k x2
= ½ x 320 x (1.5 x 10-2)2
= 3.6 x 10-2 J 
