Specific activity several other biomedical applications. Specific activity Specific activity is the activity per quantity of a radionuclide and is a physical property of that radionuclide. Activity is a quantity related to radioactivity. The SI unit of activity is the becquerel (Bq), equal to one reciprocal second. The becquerel is defined as the number of radioactive transformations per second that occur in a particular radioactive isotope. Its related non-SI unit equivalent is the Curie (Ci) which is transformations per second. Since the probability of radioactive decay for a given radionuclide is a fixed physical quantity (with some slight exceptions, see changing decay
Pascal (unit) named after Blaise Pascal, noted for his contributions to hydrodynamics and hydrostatics, and experiments with a barometer. The name pascal was adopted for the SI unit newton per square metre (N/m) by the 14th General Conference on Weights and Measures in 1971. The pascal can be expressed using SI derived units, or alternatively solely SI base units, as: where N is the newton, m is the metre, kg is the kilogram, s is the second, and J is the joule. One pascal is the pressure exerted by a force of magnitude one newton perpendicularly upon an area of one square