Question

Different units for the same Physical Quantity.

Answer 1

In physics, the units are the standards for the measurement of the physical quantities for which the requirements must be clear and to be useful. Units are the accepted standards for measurements of the physical quantities, internationally.

Complete answer:
Different types of system of units are –
(a) SI (International system of units): The SI units are the standards of measurement well-defined by the international system of units. There is basic seven SI units which includes of-
- Length – meter
- Time – second
- Amount of substance- mole
- Electric current – Ampere
- Temperature – Kelvin
- Luminous intensity – candela
- Mass - kilogram

(b) FPS (foot-pound-second) system: FPS system is the system of units in which the length is measured in foot, mass in pounds and time in seconds. Generally, the FPS system is used in the United States among the engineers.

(c) MKS (Meter-kilogram-second) system: MKS system is the system of units in which the length is measured in meters, mass in kilogram and time in seconds. Generally, MKS systems are used in engineering sectors and in advanced physics.

(d) CGS (centimetre-gram-second) system: CGS system is the system of units in which length is measured in centimetres, mass in grams and time in seconds. Most commonly, CGS systems are used in theoretical studies of physics.

Note: It is very important to know the difference between the system of units and the conversional ratios between them. Since when we say physical quantity mass of one it does not make any sense or meaning, also mass of one gram and one kilogram varies a lot as $1kg = 1000g$.