JEE Main 20127 MayOnline
- Exam
- JEE Main
- Year
- 2012
- Date
- 7 May
- Mode
- Online
- Subject
- Physics
- Chapter
- Mechanical Properties of Solids
JEE Main 2012 · 7 May · Online · Physics · Mechanical Properties of Solids
A structural steel rod has a radius of 10 ~mm and length of 1.0 ~m...
A structural steel rod has a radius of and length of . A force stretches it along its length. Young's modulus of structural steel is . The percentage strain is about
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
Given: radius $\mathrm{r}=10 \mathrm{~mm}=10^{-2} \mathrm{~m}$
From formula, $Y=\frac{\text{ Stress }}{\text{ Strain }}$
\Rightarrow \quad $\text{ Strain }=\frac{\text{ Stress }}{Y}=\frac{F}{A Y}\begin{aligned}& =\frac{10^5}{\pi r^2 Y}=\frac{10^5}{3.14 \times 10^{-4} \times 2 \times 10^{11}}\\
& =\frac{1}{628}
\end{aligned}$\%