A tension bar is found to taper uniformly from the diameter (D - a) to (D + a). If mean diameter is used in the calculation of Young Modulus, the error involved will be
1
\({\left( {\frac{{10a}}{D}} \right)^2}\)
2
\({\left( {\frac{{10D}}{a}} \right)^2}\)
3
\({\left( {\frac{{10D}}{a}} \right)}\)
4
\(\left( {\frac{{10}}{D}} \right)\)