A liquid carries high-frequency sound waves of frequency $2.0\,\text{MHz}$ at a speed of $2.0\,\text{km s}^{-1}$. What is the minimum separation between a compression and a rarefaction (expansion) in the liquid?
- A$0.5\,\text{mm}$
- B$1.0\,\text{mm}$
- C$5.0\,\text{mm}$
- D$10.0\,\text{mm}$