JEE Mains · Physics · STD 11- 8. mechanical properties of solids
The speed of a longitudinal wave in a metallic bar is \(400~m/s.\) If the density and Young's modulus of the bar material are increased by 0.5% and 1% respectively then the speed of the wave is changed approximately to ___________ \(m / s\).
- A 399
- B 398
- C 402
- D 401
Answer & Solution
Correct Answer
(D) 401
Step-by-step Solution
Detailed explanation
\(V_{sound}=\sqrt{\frac{Y}{\rho}}\) \(\frac{\Delta V}{V}\times100=\frac{1}{2}(\frac{\Delta Y}{Y}\times100)-\frac{1}{2}(\frac{\Delta\rho}{\rho}\times100)\) \(=\frac{1}{2}\times1-\frac{1}{2}\times0.5\) \(\frac{\Delta V}{V}\times100=\frac{1}{4}\)…
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