In the CGS system, Young's modulus of a steel wire is 2×1012 dyne/cm2. To double the length of a wire of unit cross-section area, the force required is:
1. 4×106 dynes
2. 2×1012 dynes
3. 2×1012 newtons
4. 2×108 dynes
Steel and copper wires of the same length and area are stretched by the same weight one after the other. Young's modulus of steel and copper are \(2\times10^{11} ~\text{N/m}^2\) and \(1.2\times10^{11}~\text{N/m}^2\). The ratio of increase in length is:
1. | \(2 \over 5\) | 2. | \(3 \over 5\) |
3. | \(5 \over 4\) | 4. | \(5 \over 2\) |
Two wires of copper having length in the ratio of 4: 1 and radii ratio of 1: 4 are stretched by the same force. The ratio of longitudinal strain in the two will be:
1. 1: 16
2. 16: 1
3. 1: 64
4. 64: 1
The work done in stretching an elastic wire per unit volume is:
1. | \(\times\)strain | stress
2. | \(\frac{1}{2}\)\(\times\) stress\(\times\)strain |
3. | \(2\times\) stress\(\times\)strain |
4. | stress/strain |
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 Young's modulus of a wire is Y. If the energy per unit volume is E, then the strain will be:
1.
2.
3.
4.
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.
2.
3.
4.
The work done per unit volume to stretch the length of a wire by 1% with a constant cross-sectional area will be:
1.
2.
3.
4.
lf is the density of the material of a wire and is the breaking stress, the greatest length of the wire that can hang freely without breaking is:
1.
2.
3.
4.
A material has Poisson's ratio of 0.5. If a uniform rod made of it suffers a longitudinal strain of , what is the percentage increase in volume?
1. 2%
2. 4%
3. 0%
4. 5%