For a fluid which is flowing steadily, the level in the vertical tubes is best represented by

Options

A.
B.
C.
D.

Explanation

To solve the problem regarding the fluid levels in vertical tubes for a fluid flowing steadily, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Steady Flow**:
- In a steady flow of fluid, the velocity and pressure at any point in the fluid do not change over time. This means that the fluid's behavior can be analyzed using principles from fluid dynamics.

2. **Apply Bernoulli's Equation**:
- For a fluid flowing horizontally, Bernoulli's equation can be expressed as:
\[ P + \frac{1}{2} \rho v^2 = \text{constant} \]
- Here, \(P\) is the pressure, \(\rho\) is the fluid density, and \(v\) is the fluid velocity.

3. **Analyze the Relationship Between Pressure and Velocity**:
- According to Bernoulli's principle, if the velocity of the fluid increases, the pressure must decrease to maintain the constant sum of pressure and kinetic energy. Conversely, if the pressure increases, the velocity must decrease.

4. **Consider the Venturi Effect**:
- In a Venturi meter, there are two sections: a wider section (A) and a narrower section (B).
- By the continuity equation, the fluid velocity in the narrower section (B) will be greater than in the wider section (A) because the flow rate must remain constant.

5. **Determine Pressure Differences**:
- Since the velocity in section B is greater than in section A, according to Bernoulli's principle, the pressure in section A (P1) must be greater than the pressure in section B (P2):
\[ P1 > P2 \]

6. **Relate Pressure to Fluid Levels**:
- The pressure difference between the two sections will cause the fluid to rise higher in the tube connected to the wider section (A) compared to the tube connected to the narrower section (B). This means the fluid level in tube A will be higher than in tube B.

7. **Select the Correct Option**:
- Based on the analysis, the correct representation of the fluid levels in the vertical tubes is that the level in the wider tube (A) is higher than in the narrower tube (B). Therefore, the correct answer is option A.

### Final Answer:
- The level in the vertical tubes is best represented by option A, where the fluid level in tube A is higher than in tube B.