Why mks system had to be rationalised to obtain SI ? Define the unit of temperature on SI.

Explanation

### Step-by-Step Solution

1. **Understanding the MKS System**: The MKS system is a metric system of measurement that stands for Meter-Kilogram-Second. While it provides a basic framework for measuring length, mass, and time, it lacks coherence in its unit definitions and relationships among different physical quantities.

2. **Need for Rationalization**: The MKS system had to be rationalized to obtain the SI (International System of Units) because the SI system aims to provide a more coherent and universally accepted framework. Rationalization involves ensuring that the units are logically related and consistent, making it easier to convert between units and apply them in scientific calculations.

3. **Advantages of the SI System**: The SI system is designed to be universally applicable and is used by all countries, which helps in standardizing measurements across different scientific fields. This system is more systematic and provides a clear relationship between different units, making it superior to the MKS system.

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