To break a wire, a force of \(10^6~\text{N/m}^{2}\) is required. If the density of the material is \(3\times 10^{3}~\text{kg/m}^3,\) then the length of the wire which will break by its own weight will be:
1. \(34\) m
2. \(30\) m
3. \(300\) m
4. \(3\) m
The bulk modulus of water is \(2\times 10^{9}~\text{N/m}^2\). The increase in pressure required to decrease the volume of water sample by \(0.1\%\) is:
1. \(4 \times 10^{6}~\text{N/m}^2\)
2. \(2 \times 10^{6}~\text{N/m}^2\)
3. \(2 \times 10^{8}~\text{N/m}^2\)
4. \(8 \times 10^{6}~\text{N/m}^2\)
One end of a uniform wire of length \(L\) and of weight \(W\) is attached rigidly to a point in the roof and a weight \(W_1\) is suspended from its lower end. If \(A\) is the area of cross-section of the wire, the stress in the wire at a height \(\frac{3L}{4}\) from its lower end is:
1. \(\frac{W+W_1}{A}\)
2. \(\frac{4W+W_1}{3A}\)
3. \(\frac{3W+W_1}{4A}\)
4. \(\frac{\frac{3}{4}W+W_1}{A}\)
The length of elastic string, obeying Hooke's law is \(l_1\) metres when the tension is \(4~\text{N}\), and \(l_2\) metres when the tension is \(5~\text{N}\). The length in metres when the tension is \(0~\text{N}\) will be:
1. \(5l_1-4l_2\)
2. \(5l_2-4l_1\)
3. \(9l_1-8l_2\)
4. \(9l_2-8l_1\)
Two wires are made of the same material and have the same volume. The first wire has a cross-sectional area \(A\) and the second wire has a cross-sectional area \(3A\). If the length of the first wire is increased by \(\Delta l\) on applying a force \(F\), how much force is needed to stretch the second wire by the same amount?
1. | \(9F\) | 2. | \(6F\) |
3. | \(4F\) | 4. | \(F\) |
Copper of fixed volume \(V\) is drawn into a wire of length \(l.\) When this wire is subjected to a constant force \(F,\) the extension produced in the wire is \(\Delta l.\) Which of the following graphs is a straight line?
1. \(\Delta l ~\text{vs}~\frac{1}{l}\)
2. \(\Delta l ~\text{vs}~l^2\)
3. \(\Delta l ~\text{vs}~\frac{1}{l^2}\)
4. \(\Delta l ~\text{vs}~l\)
Overall changes in volume and radius of a uniform cylindrical steel wire are \(0.2\%\) and \(0.002\%\) respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire is: \(\left(2.0\times 10^{11}~\text{Nm}^{-2}\right)\)
1. \(3.2\times 10^{11}~\text{Nm}^{-2}\)
2. \(3.2\times 10^{7}~\text{Nm}^{-2}\)
3. \(3.6\times 10^{9}~\text{Nm}^{-2}\)
4. \(3.9\times 10^{8}~\text{Nm}^{-2}\)
A uniform cylinder rod of length \(L\), cross-sectional area \(A\) and Young's modulus \(Y\) is acted upon by the forces, as shown in the figure. The elongation of the rod is:
1. | 2. | ||
3. | 4. |
The density of metal at normal pressure is \(\rho\). lts density when it is subjected to an excess pressure \(P\) is \(\rho'\). lf \(B\) is the bulk modulus of the metal, the ratio \(\frac{ρ'}{\rho }\) is:
1. \(\frac{1}{1-\frac{p}{B}} \)
2. \(1+\frac{B}{P} \)
3. \(\frac{1}{1-\frac{B}{P}} \)
4. \(2+\frac{P}{B}\)
1. | \(25\) m | 2. | \(100\) m |
3. | \(200\) m | 4. | \(500\) m |