How is pressure of a gas defined ?

Options

A. Mass per unit area
B. Mass per unit volume
C. Force per unit area
D. Mass per unit acceleration

Answer

To define the pressure of a gas, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Pressure**: Pressure is a physical quantity that describes the force exerted per unit area. It is a measure of how much force is acting on a given area.

2. **Formula for Pressure**: The mathematical expression for pressure (P) is given by the formula:
\[ P = \frac{F}{A} \]
where \( P \) is the pressure, \( F \) is the force applied, and \( A \) is the area over which the force is distributed.

3. **Gas Molecules in Motion**: In a gas, the molecules are in constant motion. They collide with the walls of their container, exerting force on these walls.

4. **Force Exerted by Gas Molecules**: Each collision of a gas molecule with the wall of the container exerts a small force. The total force exerted by all the gas molecules on the walls of the container contributes to the overall pressure.

5. **Pressure as a Result of Collisions**: The pressure of the gas is thus a result of these continuous collisions of gas molecules with the walls of the container. The more frequent and forceful the collisions, the higher the pressure.

6. **Conclusion**: Therefore, the pressure of a gas can be defined as the force exerted by gas molecules per unit area of the container's walls.

### Final Answer:
Pressure of a gas is defined as the force per unit area exerted by the gas molecules on the walls of its container.

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