Easy MCQ +4 / -1 PYQ · JEE Mains 2023

For a solid rod, the Young's modulus of elasticity is $3.2 \times 10^{11} \mathrm{Nm}^{-2}$ and density is $8 \times 10^3 \mathrm{~kg} \mathrm{~m}^{-3}$. The velocity of longitudinal wave in the rod will be.

  1. A $3.65 \times 10^3 \mathrm{~ms}^{-1}$
  2. B $6.32 \times 10^3 \mathrm{~ms}^{-1}$ Correct answer
  3. C $18.96 \times 10^3 \mathrm{~ms}^{-1}$
  4. D $145.75 \times 10^3 \mathrm{~ms}^{-1}$

Solution

$v=\sqrt{\frac{Y}{\rho}}=\sqrt{\frac{3.2 \times 10^{11}}{8 \times 10^{3}}}$ <br/><br/>$$ \begin{aligned} & =\sqrt {0.4 \times {{10}^8}} \\\\ & = \sqrt {40 \times {{10}^6}} \\\\ & =6.32 \times 10^{3} \mathrm{~m} / \mathrm{s} \end{aligned} $$

About this question

Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity

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