Why does India maintain its own measurement standards? Here at the National Physical Laboratory, India’s measurement standards laboratory in New Delhi, those standards are maintained. It is the custodian of national standards. The National Physical Laboratory maintains standards of SI units in India. It calibrates the national standards of weights and measures.
The National Physical Laboratory was conceptualized in 1943. The Governing Body of the Council of Scientific and Industrial Research created it. Pandit Jawaharlal Nehru laid the foundation stone on January 4, 1947. The main building opened on January 21, 1950. Sardar Vallabhbhai Patel, the Former Deputy Prime Minister, formally opened it.
The National Physical Laboratory strengthens physics-based research. It helps the overall development of science and technology in India. The lab establishes and maintains national measurement standards. These standards benefit the nation. They realize the units based on the International System. The National Physical Laboratory conducts research in physics areas. This research is appropriate to the needs of the nation. It helps advance the field.
The National Physical Laboratory assists industries and national agencies. It aids their developmental tasks. It provides precision measurements and calibration. It develops devices and processes. It solves problems related to physics. The National Physical Laboratory studies the status of physics.
In 1957, India joined the General Conference of Weight and Measures. Dr. K. S. Krishnan signed the Metre Convention. He was the Director of CSIR-NPL. He signed on behalf of the Government of India. In 1958, BIPM provided CSIR-NPL copies of international prototypes. These prototypes were for the kilogram and the metre. This was a milestone. It helped establish quality infrastructure in independent India.
By 1960, the metric system was the basis for SI units. The number of base units at the National Physical Laboratory increased. Other physical standards were acquired. These included standard cells and resistance coils. Calibration and testing work began in these areas. The lab maintains six SI base units. These are metre, kilogram, second, kelvin, ampere, and candela.
Each modernized country has a National Metrological Institute. This institute maintains measurement standards. In India, this responsibility belongs to the National Physical Laboratory.
The unit of length, the metre, uses a stabilized helium-neon laser. Its frequency is measured experimentally. The wavelength is determined using the speed of light. An optical interferometer measures length using the laser light’s wavelength.
India’s national standard of mass is copy number 57. It is the international prototype of the kilogram. The International Bureau of Weights and Measures in Paris supplied it. The NPL maintains transfer standard kilograms. These are made of stainless steel and nickel-chromium alloy.
The National Physical Laboratory maintains the standard of time interval. It also maintains frequency. This is done through four parameters. The lab links these standards to different users. This dissemination happens in several ways. Satellite-based dissemination uses the Indian national satellite, INSAT. Time is also disseminated through TV, radio, and telephone services.
The unit of electric current, ampere, is realized by measuring volt and ohm. The temperature standard is based on the International Temperature Scale of 1990. This scale assigns temperatures to fixed points. One fundamental temperature is the triple point of water. The National Physical Laboratory maintains temperature standards. They cover a range from 54 to 2,473 kelvins.
The unit of luminous intensity, candela, uses an absolute radiometer. Tungsten incandescent lamps are used for practical work.
The National Physical Laboratory develops Indian reference materials. These materials derive their traceability from National Standards. One important research activity is the indelible ink. This ink is used in Indian elections. It prevents fraudulent voting.
The standards at the National Physical Laboratory are compared with standards worldwide. This ensures Indian standards are equivalent globally. The National Physical Laboratory calibrates measurement standards. It maintains a chain of laboratories across different states. It ensures measurements are linked to national and international standards.
So, the next time you see consistent measurements, remember the work of the National Physical Laboratory. It quietly ensures accuracy. It supports India’s progress in science and industry.