Radioactive Decay Calculator
Calculate the remaining amount of a radioactive substance after a given time using its half-life. Free nuclear physics decay calculator with curves and breakdowns.
About This Calculator
The Radioactive Decay Calculator computes the amount of a radioactive substance remaining after a given time. Using the initial amount, half-life, and elapsed time, it calculates remaining material, decayed amount, and the decay constant.
Radioactive decay follows first-order kinetics described by N(t) = N0 · e-lambdat where lambda (decay constant) = ln(2)/t1/2. This exponential decay model applies to all radioactive isotopes regardless of the type of radiation emitted.
Applications of Radioactive Decay Calculations
Radioactive decay calculations are essential in nuclear physics, radiometric dating (carbon-14, uranium-lead), nuclear medicine (dosimetry, tracer studies), radioactive waste management, and environmental monitoring of fallout and contamination.
Frequently Asked Questions
What is radioactive decay?
Radioactive decay is the spontaneous process where unstable atomic nuclei lose energy by emitting radiation. The decay follows first-order kinetics: N(t) = N0e^(-lambdat) where lambda = ln(2)/t1/2.
What is half-life in radioactive decay?
Half-life (t1/2) is the time required for half of the radioactive atoms to decay. Each isotope has a characteristic half-life ranging from microseconds to billions of years.
How do you calculate remaining radioactive material?
Use N(t) = N0 x e^(-lambdat) where lambda = ln(2)/t1/2. Enter the initial amount, half-life, and elapsed time to find the remaining amount and decay constant.
What types of radioactive decay exist?
Alpha decay (^4He nucleus), beta decay (electron/positron), gamma decay (high-energy photons), electron capture, and spontaneous fission. Each type has different penetrating power and biological effects.
How is radioactive decay measured?
Radioactivity is measured in becquerels (Bq = 1 decay/s) or curies (Ci = 3.7x10¹^0 Bq). Geiger-Müller counters, scintillation detectors, and semiconductor detectors are common measurement instruments.