Different Half-lives Of Radioactive Isotopes (GCSE Physics)

A sample’s activity is 3200 Bq initially. After 6 hours it is 400 Bq. What is the number of half-lives that have passed?

A medical isotope should have a short half-life to minimize patient dose but long enough to perform the procedure. Which half-life property best matches this need?

If a sample undergoes 3 half-lives, what fraction of the original nuclei remains?

Carbon-14 has half-life about 5700 years. After 11 400 years what percentage of the original C-14 remains?

An isotope has half-life 5 years. After 15 years what fraction remains?

For a given activity A and decay constant ?, which relationship between number of atoms N and activity A is correct?

An isotope has half-life 0.62 s. Which use is most likely appropriate for this isotope?

You measure that activity dropped from 10 000 Bq to 1250 Bq. How many half-lives elapsed?

If two isotopes have the same mass of sample but isotope A has a much shorter half-life than isotope B, which is true initially?

Isotope A has half-life 2 days, Isotope B half-life 10 days. Which is more suitable to use as a medical diagnostic tracer that must decay quickly?

An isotope has half-life T. Which expression gives the number of half-lives elapsed in time t?