exponential decay

Exponential decay describes a process where a quantity decreases at a rate proportional to its current value. This is mathematically represented by an exponential function where the base is between 0 and 1, or by a negative exponent.1

In physics, exponential decay is commonly observed in radioactive decay, where unstable atomic nuclei spontaneously transform into other species by emitting particles and energy. The rate of this decay is characterized by a decay constant.23

A key concept related to radioactive decay is half-life, which is the time it takes for half of a radioactive sample to decay. For example, cobalt-60 has a half-life of 5.26 years; after this period, a sample will contain only half the original amount of cobalt-60. This principle applies to many natural processes, including heat loss and population growth, where the rate of change is directly dependent on the current value.24