Write the full form of CGS, FPS, MKS, and SI?
Here’s a detailed full form of CGS, FPS, MKS, and SI, highlighting their key features and historical context:
1. CGS (Centimeter-Gram-Second system)
Origin – Developed in the 19th century, CGS was once the dominant system in scientific measurements.
Units
Length: Centimeter (cm)
Mass: Gram (g)
Time: Second (s)
Variants – Several variants exist, focusing on different areas like electrostatics (CGSE) or magnetism (CGSG).
Current Status – Largely replaced by the SI system due to its coherence and simplicity.
2. FPS (Foot-Pound-Second system)
Geographical Reach – Primarily used in the United States and to some extent in Canada.
Units
Length: Foot (ft)
Mass: Pound (lb) (Important Note: There are different types of pounds, so clarification might be necessary)
Time: Second (s)
Applications – Common in everyday use (carpentry, sports) but not scientific research due to incompatibility with SI.
3. MKS (Meter-Kilogram-Second system)
Historical Significance – A precursor to the SI system, MKS laid the foundation for a more standardized approach.
Unit
Length: Meter (m)
Mass: Kilogram (kg)
Time: Second (s)
Advantages over CGS & FPS – Decimal base and more logical selection of fundamental units.
Limitations – Lacked a complete set of well-defined units for all quantities, leading to the development of SI.
4. SI (International System of Units)
Global Standard – The modern go-to system for measurements, widely adopted in science, engineering, and many other fields.
Coherence – All units are derived from a set of seven fundamental units, ensuring consistency.
Fundamental Units
Length: Meter (m)
Mass: Kilogram (kg)
Time: Second (s)
Electric Current: Ampere (A)
Thermodynamic Temperature: Kelvin (K)
Luminous Intensity: Candela (cd)
Amount of Substance: Mole (mol)
Differences and Why SI Reigns Supreme
- Comprehensiveness – SI provides a complete set of units for all physical quantities, unlike MKS.
- Coherence – SI units are all interrelated logically, simplifying calculations and avoiding conversion headaches.
- Global Acceptance – SI is the international standard, fostering collaboration and clear communication in science and technology.
While CGS, FPS, and MKS played historical roles, SI’s coherence, comprehensiveness, and global acceptance make it the dominant measurement system today.

