Which one is not a unit of pressure ?

Options

A. `Nm^(-2)`
B. Pascal
C. `Nm^(-1)`
D. Dyne `Cm^(-2)`

Explanation

To determine which option is not a unit of pressure, we need to understand the definition of pressure and the units associated with it.

### Step-by-Step Solution:

1. **Understanding Pressure**:
- Pressure is defined as the force applied per unit area. The formula for pressure (P) is given by:
\[ P = \frac{F}{A} \]
where \( F \) is the force and \( A \) is the area.

2. **Identifying Units of Force and Area**:
- The SI unit of force is Newton (N).
- The SI unit of area is square meter (m²).

3. **Deriving the Unit of Pressure**:
- From the definition, the unit of pressure can be derived as:
\[ \text{Pressure} = \frac{\text{Force}}{\text{Area}} = \frac{\text{Newton}}{\text{meter}^2} = \text{Newton per meter square (N/m²)} \]
- This unit is also known as Pascal (Pa), where:
\[ 1 \text{ Pascal} = 1 \text{ N/m²} \]

4. **Evaluating the Given Options**:
- **Newton per meter square (N/m²)**: This is a unit of pressure (1 Pascal).
- **Pascal (Pa)**: This is also a unit of pressure.
- **Dine centi per meter square (dyn/cm²)**: This is another unit of pressure.
- **Newton per meter (N/m)**: This is not a unit of pressure; it represents force per unit length, not force per unit area.

5. **Conclusion**:
- The option that is not a unit of pressure is **Newton per meter (N/m)**.

### Final Answer:
**Newton per meter (N/m) is not a unit of pressure.**

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