**
Which of the factors primarily decide whether the flow in a circular pipe is laminar or turbulent?**

**(A)**The Prandtl number

**(B)**The pressure gradient along the length of the pipe

**(C)**The dynamic viscosity coefficient

**(D)**The Reynolds number

**D**

**
Which of the followings has the form of Reynolds number?**

**(A)**$\frac{\Delta P}{\rho {V}^{2}}$

**(B)**$\frac{\rho {V}^{2}L}{\mu}$

**(C)**$\frac{\rho VD}{\mu}$

**(D)**$\frac{\rho VD}{\nu}$

**C**

**
In the flow through a pipe, the transition from laminar to turbulent flow does not depend on**

**(A)**the velocity of the fluid

**(B)**the density of the fluid

**(C)**the diameter of the pipe

**(D)**the length of the pipe

**D**

**
A large Reynolds number is an indication of**

**(A)**smooth and streamline flow

**(B)**laminar flow

**(C)**steady flow

**(D)**turbulent flow

**D**

**
The flow through a circular pipe is laminar. Now, the fluid through the pipe is replaced with a more viscous fluid and passed through the pipe again with the same velocity. What can we say about the nature of this flow?**

**(A)**The flow will become turbulent

**(B)**The flow will be a transition flow

**(C)**The flow will remain laminar

**(D)**The Reynolds number of the earlier flow is required to answer this question

**C**