A metal rod of Young's modulus Y and coefficient of thermal expansion is held at its two ends such that its length remains invariant. If its temperature is raised by , the linear stress developed in it is:
1.
2.
3.
4.
An external pressure \(P\) is applied on a cube at \(0^\circ\text{C}\) so that it is equally compressed from all sides. \(K\) is the bulk modulus of the material of the cube and \(\alpha\) is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by:
1. \( \dfrac{{P}}{3 \alpha {K}}\)
2. \( \dfrac{{P}}{\alpha{K}} \)
3. \( \dfrac{3 \alpha}{{PK}} \)
4. \(3 {PK} \alpha\)
| 1. | \(1.5~\times~ 10^{-5} /^\circ \text{C}\) | 2. | \(1.2~\times~ 10^{-5} /^\circ \text{C}\) |
| 3. | \(0.6~\times~ 10^{-5} /^\circ \text{C}\) | 4. | \(0.75~\times~ 10^{-5} /^\circ \text{C}\) |
| 1. | \( \dfrac{F} { {A} \alpha \Delta{T}}\) | 2. | \( \dfrac{F} { {A} \alpha (\Delta{T}-273)}\) |
| 3. | \( \dfrac{F} { 2{A} \alpha \Delta{T}}\) | 4. | \( \dfrac{2F} { {A} \alpha \Delta{T}}\) |