Negative frequency Negative frequency The concept of negative and positive frequency can be as simple as a wheel rotating one way or the other way: a "signed value" of frequency can indicate both the rate and direction of rotation. The rate is expressed in units such as revolutions (a.k.a. "cycles") per second (hertz) or radian/second (where 1 cycle corresponds to 2"π" radians). Let "ω" be a nonnegative parameter with units of radians/sec. Then the angular function (angle vs. time) , has slope −"ω", which is called a negative frequency. But when the function is used as the argument of a cosine operator,
Radioactive decay Protection (ICRP) was born. Since then the ICRP has developed the present international system of radiation protection, covering all aspects of radiation hazard. The International System of Units (SI) unit of radioactive activity is the becquerel (Bq), named in honor of the scientist Henri Becquerel. One Bq is defined as one transformation (or decay or disintegration) per second. An older unit of radioactivity is the curie, Ci, which was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)". Today, the curie is defined as disintegrations per second, so that 1 curie