A wire of length \(L\), area of cross section \(A\) is hanging from a fixed support. The length of the wire changes to \(\mathrm{L}_1\)when mass \(M\) is suspended from its free end. The expression for Young's modulus is:
1. | \(\frac{{Mg(L}_1-{L)}}{{AL}}\) | 2. | \(\frac{{MgL}}{{AL}_1}\) |
3. | \(\frac{{MgL}}{{A(L}_1-{L})}\) | 4. | \(\frac{{MgL}_1}{{AL}}\) |