Q: If Young’s modulus of the material of a rod is Y and density is ρ then time taken by sound wave to travel *l* length from bottom is

(a) $\displaystyle l \sqrt{\frac{\rho}{Y}}$

(b) $ \displaystyle l \sqrt{\frac{Y}{\rho}}$

(c) $ \displaystyle \frac{1}{l} \sqrt{\frac{Y}{\rho}}$

(d) $ \displaystyle \frac{1}{l} \sqrt{\frac{\rho}{Y}}$

Ans: (a)