Question

Water is flowing through a horizontal pipe in a streamline flow. At the narrowest part of the pipe

• A. velocity is maximum and pressure is minimum.
• B. pressure is maximum and velocity is minimum.
• C. both the pressure and velocity are minimum.
• D. both the pressure and velocity are maximum.

Hint:

Rule: Narrow pipe $\rightarrow$ Fast flow $\rightarrow$ Low pressure

Answer 1

The Correct Option is A

Concept: From continuity equation and Bernoulli’s theorem: \[ A v = \text{constant} \quad \text{and} \quad P + \frac{1}{2}\rho v^2 = \text{constant} \]

Step 1: Continuity equation.
Narrower area $\Rightarrow$ higher velocity.

Step 2: Bernoulli’s principle.
Higher velocity $\Rightarrow$ lower pressure.

Step 3: Conclusion.
At narrowest part: velocity maximum, pressure minimum. Final Answer: Option (A)