Explanation of tensile stress and Young’s modulus were poorly stated by majority of the candidates. While many scored for valid additional information, many others failed to relate tensile stress with a wire or rod.
The expected answers are:
(a) Tensile stress is the ratio of force to cross-sectional area of a wire/rod
It is expressed in Newton per metre squared (Nm-2)
(b) Young’s modulus is the ratio of tensile stress to tensile strain. It is expressed in Newton per metre squared. (Nm-2)