Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Heat and Temperature
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Heat and Temperature
A steel rod of length 1 m is placed on a smooth horizontal base....
A steel rod of length is placed on a smooth horizontal base. When it is heated from 0^{}^{{}^{\circ}} \text{C} to 100^{}^{{}^{\circ}} \text{C}, what is the longitudinal strain developed?
Options
- A
- B
- CZero
- D
Correct answer
C. Zero
Step-by-step solution
When a rod is heated, it undergoes thermal expansion.
If the rod is free to expand, such as when it is placed on a smooth horizontal base, no internal restoring forces are generated within the material. Thermal stress is developed only when the natural expansion of the rod is restricted by external forces or supports.
Since there is no restriction on the expansion of the steel rod in this case, the thermal stress developed is zero.
According to Hooke's law, the mechanical strain developed is directly proportional to the stress. Because the stress is zero, the longitudinal strain developed in the rod is also zero. (Note that the actual change in length is not considered as mechanical strain unless it is caused by a deforming force).
If the rod is free to expand, such as when it is placed on a smooth horizontal base, no internal restoring forces are generated within the material. Thermal stress is developed only when the natural expansion of the rod is restricted by external forces or supports.
Since there is no restriction on the expansion of the steel rod in this case, the thermal stress developed is zero.
According to Hooke's law, the mechanical strain developed is directly proportional to the stress. Because the stress is zero, the longitudinal strain developed in the rod is also zero. (Note that the actual change in length is not considered as mechanical strain unless it is caused by a deforming force).