Observation

This was a popular question among candidates. (a) The questions tested the various stages involved in extension of elastic materials. Majority of the candidates performed averagely in (a) while in (b) some candidates gave the correct S.I unit of Young’s modulus as Nm^-2, other candidates stated differently as N/m^-2. Performance was below average.

The expected response is as stated below:

1. Definition of yield point of an elastic material
   The Stress/Force above which the material loses its elasticity (permanently). NOTE: Accept “point” in place of stress/force.
2. The S.I. unit of Young’s modulus
   N m^-2