- 1(current)
Q. No.The pressure that has to be applied to the ends of a steel wire of length \(10~\text{cm}\) to keep its length constant when its temperature is raised by \(100^\circ \text{C}\) is:
(Young's modulus of steel is \(2\times 10^{11}~\text{Nm}^{-2}\) and coefficient of thermal expansion is \(1.1 \times 10^{-5}~\text{K}^{-1}\))
1. \( 2.2 \times 10^9 ~\text{Pa} \)
2. \( 2.2 \times 10^7 ~\text{Pa} \)
3. \( 2.2 \times 10^6 ~\text{Pa} \)
4. \( 2.2 \times 10^8 ~\text{Pa} \)
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. \(2\times10^{9}~\text{N}\)
2. \(3\times 10^{-5}~\text{N}\)
3. \(2\times10^{7}~\text{N}\)
4. \(1\times10^{5}~\text{N}\)
Given below are two statements:
| Assertion (A): | When a rod lying freely is heated, no thermal stress is developed in it. |
| Reason (R): | On heating the length of the rod increases. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
- 1(current)
Q. No.
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