For laminar flow the value of reynolds number is

Options

A. Greater than 1000 but less than 2000
B. Less than 1000
C. Greater than 2000 but less than 3000
D. Greater than 3000

Answer

To determine the value of the Reynolds number for laminar flow, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Reynolds Number**:
The Reynolds number (Re) is a dimensionless quantity used to predict flow patterns in different fluid flow situations. It is defined as:
\[ Re = \frac{\rho v d}{\eta} \]
where:
- \( \rho \) = density of the fluid
- \( v \) = velocity of the fluid
- \( d \) = diameter of the pipe
- \( \eta \) = dynamic viscosity of the fluid

2. **Identify the Conditions for Laminar Flow**:
Laminar flow occurs when the fluid flows in parallel layers with minimal disruption between them. The flow is considered laminar when the Reynolds number is below a certain threshold.

3. **Determine the Threshold Value**:
According to fluid dynamics, the flow is classified as:
- **Laminar Flow**: \( Re < 1000 \)
- **Transitional Flow**: \( 1000 < Re < 3000 \)
- **Turbulent Flow**: \( Re > 3000 \)

4. **Conclude the Value of Reynolds Number for Laminar Flow**:
From the above classifications, we conclude that for laminar flow, the value of the Reynolds number must be less than 1000.

### Final Answer:
For laminar flow, the value of the Reynolds number is less than 1000.

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