Longitudinal strain $\frac{l}{L} = \frac{{{\rm{stress}}}}{Y} = \frac{{{{10}^7}}}{{{{10}^{11}}}} = {10^{ - 4}}$
Percentage increase in length $ = {10^{ - 4}} \times 100 = 0.01\% $

Assertion $A$: Steel is used in the construction of buildings and bridges.
Reason $R:$ Steel is more elastic and its elastic limit is high.
In the light of above statements, choose the most appropriate answer from the options given below
