The speed $v$ at which a liquid exits a tube is affected by the pressure change $\Delta P$ and the liquid density $\rho$. This speed is described by $v = k \left( \frac{\Delta P}{\rho} \right)^n$ where $k$ is a constant with no units. What is the value of $n$?
- A$\frac{1}{2}$
- B$1$
- C$\frac{3}{2}$
- D$2$