National Physical Laboratory of India users. This process, known as dissemination, is carried out in a number of ways. For applications requiring low levels of uncertainty, there is satellite based dissemination service, which utilizes the Indian national satellite, INSAT. Time is also disseminated through TV, radio, and special telephone services. The caesium atomic clocks maintained at NPL are linked to other such instituted all over the world through a set of global positioning satellites. The unit of electric current, ampere, is realized at NPL by measuring volt and Ohm separately. The uncertainty in measurement of ampere is ± 1 × 10. The standard of temperature
Electrical resistance and conductance referred to as a "chordal resistance" or "static resistance", since it corresponds to the inverse slope of a chord between the origin and an "I–V" curve. In other situations, the derivative formula_2 may be most useful; this is called the "differential resistance". In the hydraulic analogy, current flowing through a wire (or resistor) is like water flowing through a pipe, and the voltage drop across the wire is like the pressure drop that pushes water through the pipe. Conductance is proportional to how much flow occurs for a given pressure, and resistance is proportional to how much pressure is required