Majority of the responding candidates defined 'tensile strain' correctly as well as identified correctly 'spring balance' as an instrument that operates on the principle of Hooke's law. However, very few candidates succeeded in identifying K as elastic constant/stiffness/force constant in the given equation:F = Ke. Generally performance was good.

The expected answers are:

(a) Tensile strain is the ratio of extension to original length. (mathematical definition is acceptable jf symbols are defmed).
(b)Spring balance
(c) Elastic constant/stiffness