Preparation Staff asked 4 weeks ago The SI unit of mass is the kilogram (kg). The kilogram is one of the seven base units of the SI system and serves as the standard unit for measuring the amount of matter in an object. It is the only base unit that is still defined by a physical object – a platinum-iridium cylinder known as the international prototype of the kilogram.
The kilogram was historically defined as the mass of this physical prototype, but in 2019, the definition was redefined in terms of the Planck constant (h), a fundamental constant of nature. This shift was made to ensure that the kilogram’s definition is independent of any physical object and based on a constant of nature, which is more stable and reproducible.
1 kilogram is defined as the mass of an object that has a value of 6.62607015 × 10⁻³⁴ joule-seconds for the Planck constant, which is a measure of the smallest possible unit of energy in quantum mechanics. This redefinition ensures that the kilogram is determined by a universal constant that is precise and constant over time.
The kilogram is used extensively in science, industry, and daily life. It serves as the foundation for measuring the mass of objects, whether in physics experiments, manufacturing, or food production. The precision of the kilogram is essential for accurate measurements in a wide variety of applications, from research to trade.
Please login or Register to submit your answer