An elastic material of Young's modulus \(Y\) is subjected to a stress \(S\). The elastic energy stored per unit volume of the material is:
1. \(\frac{SY}{2}\)
2. \(\frac{S^2}{2Y}\)
3. \(\frac{S}{2Y}\)
4. \(\frac{2S}{Y}\)

If \(E\) is the energy stored per unit volume in a wire having \(Y\) as Young's modulus of the material, then the stress applied is:
1. \(\sqrt{2EY}\)
2. \(2\sqrt{EY}\)
3. \(\frac{1}{2}\sqrt{EY}\)
4. \(\frac{3}{2}\sqrt{EY}\)

The Young's modulus of a wire is \(Y\).  If the energy per unit volume is \(E\), then the strain will be:
1. \(\sqrt{\frac{2E}{Y}}\)
2. \(\sqrt{2EY}\)
3. \(EY\)
4. \(\frac{E}{Y}\)

A wire of length \(L\) and cross-sectional area \(A\) is made of a material of Young's modulus \(Y.\) It is stretched by an amount \(x.\) The work done is:
1. $\frac{YxA}{2L}$

2. $\frac{Y{x}^{2}A}{L}$

3. $\frac{Y{x}^{2}A}{2L}$

4. $\frac{2Y{x}^{2}A}{L}$

A \(5\) m long wire is fixed to the ceiling. A weight of \(10\) kg is hung at the lower end and is \(1\) m above the floor. The wire was elongated by \(1\) mm. The energy stored in the wire due to stretching is:
1. zero                                 
2. \(0.05\) J
3. \(100\) J                          
4. \(500\) J

The ratio of Young's modulus of the material of two wires is \(2:3\). If the same stress is applied on both, then the ratio of elastic energy per unit volume will be:
1. \(3:2\)
2. \(2:3\)
3. \(3:4\)
4. \(4:3\)

The work done per unit volume to stretch the length of a wire by \(1\%\)  with a constant cross-sectional area will be:
\(Y = 9\times10^{11}~\text{N/m}^2\)
1. \(9\times 10^{11}~\text{J}\)
2. \(4.5\times 10^{7}~\text{J}\)
3. \(9\times 10^{7}~\text{J}\)
4. \(4.5\times 10^{11}~\text{J}\)

If the force constant of a wire is \(K\), the work done in increasing the length of the wire by \(l\) is:
1. \(\frac{Kl}{2}\)
2. \(Kl\)
3. \(\frac{Kl^2}{2}\)
4. \(Kl^2\)

A wire of negligible mass and length \(2\) m is stretched by hanging a \(20\) kg load to its lower end keeping its upper end fixed. If work done in stretching the wire is \(50\) J, then the strain produced in the wire will be:
1. \(0.5\)
2. \(0.1\)
3. \(0.4\)
4. \(0.25\)