All questions of Unit for SSC CGL Exam

Understanding Measurement Systems
In the realm of scientific and engineering measurements, various systems of units are employed. The question highlights three systems: MKS, SI, and FPS.
1. MKS System
- The MKS system stands for Metre, Kilogram, Second.
- It is a coherent system of units based on the metric system.
- Length is measured in meters (m), mass in kilograms (kg), and time in seconds (s).
2. SI System
- The SI, or International System of Units, is the modern form of the metric system.
- It is globally accepted and used in scientific research, engineering, and various fields.
- The base units in SI include meter for length, kilogram for mass, and second for time, just like the MKS system.
- SI also includes additional derived units and prefixes for larger and smaller measurements.
3. Conclusion: Both MKS and SI
- Since the MKS system is a subset of the SI system, both systems measure length in meters, mass in kilograms, and time in seconds.
- Therefore, the correct answer is indeed option 'C': both MKS and SI.
4. FPS System
- For contrast, the FPS system (Foot, Pound, Second) measures length in feet, mass in pounds, and time in seconds, which is entirely different from the metric-based systems.
In summary, both the MKS and SI systems utilize the same base units for length, mass, and time, making option 'C' the accurate choice.

Definition of a Physical Quantity:
Physical quantities are properties of bodies or substances that can be measured. These measurements are expressed in numerical values and units.

Characteristics of a Physical Quantity:
- Physical quantities are measurable attributes of objects or materials.
- They can be quantified using standardized units of measurement.
- These quantities are essential for describing and understanding the physical world.

Importance of Physical Quantities:
- Physical quantities provide a basis for scientific research and experimentation.
- They allow for accurate and precise communication of measurements and observations.
- Physical quantities play a crucial role in the development of scientific theories and laws.

Examples of Physical Quantities:
- Length, mass, time, temperature, electric current, luminous intensity, amount of substance, etc.
- These quantities have both magnitude and units associated with them.

Measurement of Physical Quantities:
- Physical quantities are measured using appropriate instruments and techniques.
- Measurements are essential for evaluating the behavior and characteristics of objects and materials.
- The results of measurements are used to make predictions, analyze data, and draw conclusions in scientific investigations.
In conclusion, a physical quantity is defined as a property of a body or substance that can be measured. These quantities are fundamental in scientific research and play a crucial role in understanding the physical world.