The gauge factor of strain gauge is given by _____________.
1
\(G = \frac{{\frac{{\Delta A}}{{A}}}}{{\frac{{\Delta R}}{{R}}}}\)
2
\(G = \frac{{\frac{{\Delta R}}{{R}}}}{{\frac{{\Delta D}}{{D}}}}\)
3
\(G = \frac{{\frac{{\Delta L}}{{L}}}}{{\frac{{\Delta R}}{{R}}}}\)
4
\(G = \frac{{\frac{{\Delta R}}{{R}}}}{{\frac{{\Delta L}}{{L}}}}\)