Half-life is defined as the quantity to reduce to half of its initial value.
Step-by-step explanation:
The term half-life is generally used in nuclear physics which describes how long a stable atom can survive a radioactive decay or how quickly an unstable stable atom can undergo radioactive decay. Half-life is a constant and does not have any units.
The formula to calculate half-life:
N(t) =

Here N(t) is the quantity which is “not decayed”.
is the “initial quantity” of the substance.
λ is the “decay constant”