The 26th meeting of the General Conference on Weights and Measures (CGPM) was held at Versailles(Paris), France. The members have voted for the redefinition of 130 years old “Le grand K – the SI unit of kg” in terms of the fundamental Planck’s constant(h). The new definitions will come into force on 20 May 2019.
The definition of kilogram has been changed from being the mass of prototype sanctioned by the 1st CGPM held in Paris in 1889 and deposited at the BIPM to the Planck constant which is a physical constant. Likewise, the definition of meter has been changed to link it to the speed of light. There is a change in the definition of time also.
Source: Press Information Bureau
Static/Current Takeaways Important For IBPS Clerk Mains Exam 2018:
- The CGPM is the highest international body of the world for accurate and precise measurements.
- World Metrology Day – 20 May.
- The CGPM meets in Paris, usually once every four years.