They undergo radioactive decay.
They undergo elastic collisions with air molecules.
They ionize air molecules.
They are attracted by the nuclei of air molecules.
Total mass of the sample
Total number of atoms in the sample
Total number of nuclei in the sample
Activity of the radioactive isotope in the sample
Decreases linearly with time.
Increases linearly with time.
Decreases exponentially with time.
Increases exponentially with time.
Entirely due to nuclide X.
Due equally to nuclides X and Y.
Mostly due to nuclide X.
Mostly due to nuclide Y.
Time taken for a particle to decay
Probability of some of the substance decaying in 1 second
Probability of a particular nucleus decaying in 1 second
Probability of a particular nucleus decaying in 1 half life
The decaying nucleus emits either an a-particle, or a b-particle or a g-ray photon.
The type of radiation emitted by the decaying nucleus cannot be predicted.
The time at which a particular nucleus will decay cannot be predicted
The decay of a nucleus is unaffected by environmental conditions.