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. \(Kl^2\)

When strain is produced in a body within elastic limit, its internal energy:
1. Remains constant                  
2. Decreases
3. Increases                               
4. None of the above

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. \(\dfrac{Y x A}{2 L}\)

2. \(\dfrac{Y x^{2} A}{L}\)

3. \(\dfrac{Y x^{2} A}{2 L}\)

4. \(\dfrac{2 Y x^{2} A}{L}\)

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. \(4.5\times 10^{11}~\text{J}\)

lf \(\rho\) is the density of the material of a wire and \(\sigma\) is the breaking stress, the greatest length of the wire that can hang freely without breaking is:
1. \(\dfrac{2}{\rho g}\)

2. \(\dfrac{\rho}{\sigma g}\)

3. \(\dfrac{\rho g}{2 \sigma}\)

4. \(\dfrac{\sigma}{\rho g}\)

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. \(\frac{2S}{Y}\)

A material has Poisson's ratio of \(0.5\). If a uniform rod made of it suffers a longitudinal strain of \(2\times 10^{-3}\), what is the percentage increase in volume?
1. \(2\%\)
2. \(4\%\)
3. \(0\%\)
4. \(5\%\)

If the ratio of lengths, radii, and Young's modulus of steel and brass wires in the figure are \(a,\) \(b\) and \(c\) respectively, then the corresponding ratio of increase in their lengths will be:

                                    
1. \(\dfrac{2 a^{2} c}{b}\)

2. \(\dfrac{3 a}{2 b^{2} c}\)

3. \(\dfrac{2 a c}{b^{2}}\)

4. \(\dfrac{3 c}{2 a b^{2}}\)