JEE Mains · Physics · STD 11- 8. mechanical properties of solids
The elastic potential energy stored in a steel wire of length \(20\,m\) stretched through \(2 \,cm\) is \(80\,J\). The cross sectional area of the wire is \(.........\,mm ^2\) (Given, \(y =2.0 \times 10^{11}\,Nm ^{-2}\) )
- A \(38\)
- B \(36\)
- C \(40\)
- D \(34\)
Answer & Solution
Correct Answer
(C) \(40\)
Step-by-step Solution
Detailed explanation
Energy per unit volume \(=\frac{1}{2} \text { stress } \times \text { strain }\) Energy \(=\frac{1}{2} \text { stress } \times \text { strain } \times \text { volume }\) \(80=\frac{1}{2} \times Y \times \text { strain }^2 A \times \ell\)…
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