Which of the following statements is incorrect?

Options

A. The bulk modulus for solids is much larger than for liquids.
B. Gases are least compressible.
C. For a system in equilibrium, the value of bulk modulus is always positive.
D. The SI unit of bulk modulus is same that of pressure.

Explanation

To determine which of the statements is incorrect, let's analyze each statement step by step:

1. **Statement 1: The bulk modulus for solids is much larger than for liquids.**
- The bulk modulus is a measure of a material's resistance to uniform compression. Solids are generally less compressible than liquids because their atoms are tightly packed. Therefore, the bulk modulus for solids is indeed much larger than that for liquids.
- **Conclusion:** This statement is correct.

2. **Statement 2: Gases are least compressible.**
- Compressibility refers to how much a substance can decrease in volume under pressure. Gases have particles that are far apart and can be compressed significantly, making them the most compressible of the three states of matter (solids, liquids, and gases). Therefore, this statement is incorrect.
- **Conclusion:** This statement is incorrect.

3. **Statement 3: For a system in equilibrium, the value of bulk modulus is always positive.**
- The bulk modulus is defined as the ratio of the change in pressure to the fractional change in volume. For a system in equilibrium, the bulk modulus is indeed always positive because an increase in pressure results in a decrease in volume, and the bulk modulus is defined as a positive quantity.
- **Conclusion:** This statement is correct.

4. **Statement 4: The SI unit of bulk modulus is the same as that of pressure.**
- The bulk modulus is expressed in terms of pressure (force per unit area), and its SI unit is Pascal (Pa), which is also the SI unit for pressure. Therefore, this statement is correct.
- **Conclusion:** This statement is correct.

**Final Answer:** The incorrect statement is **Statement 2: Gases are least compressible.**

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