Strontium-90 (3890Sr\text{}^{90}_{38}\text{Sr}3890Sr) is radioactive. It decays by β\betaβ-emission to form an isotope of yttrium (Y\text{Y}Y).
Complete the nuclide equation for this decay:
3890Sr→ ......Y+ ......β \text{}^{90}_{38}\text{Sr} \rightarrow \:\: ^{...}_{...}\text{Y} + \:\: ^{...}_{...}\beta 3890Sr→......Y+......βA pure sample of strontium-90 emits β\betaβ-particles at an initial count rate of 3200 counts/second3200\text{ counts/second}3200 counts/second. The half-life of strontium-90 is 28 years28\text{ years}28 years.
Calculate the count rate from the emission of β\betaβ-particles from the strontium in the sample after 112 years112\text{ years}112 years have passed.
The isotope of yttrium in (a) is also radioactive. It decays by β\betaβ-emission and has a half-life of 64 hours64\text{ hours}64 hours.
State and explain how this would affect the observed beta count rate for the sample in (b) after 112 years112\text{ years}112 years.
144 exam-style questions on CIE IGCSE Physics 5.2.4a Half-life. Each one has a worked solution and a mark scheme showing where the marks go.