12.2 Nuclear Physics

The Physicists Geiger and Marsden bombarded a thin gold foil with alpha particles. They observed that

Select the row which explains these effects.

Two samples P and Q of different radioactive isotopes have the same initial activity. Sample P has a third of the number of atoms as sample Q. The half-life of P is T seconds.

What is the half-life of sample Q?

The half-life of a radioactive isotope is 10 days. What is the approximate percentage of the sample remaining after 25 days?

A pure sample of a radioactive nuclide undergoes a decay resulting in a stable daughter nuclide. What fraction of the sample is made up of the daughter nuclide after five half-lives?

A series of radioactive decays produce both alpha particles and anti-neutrinos. Which answer option describes the nature of the energy spectrum of these two particles?

The decay of several unstable nuclei are observed in a radiation chamber. The following identifications are made: 

1. Alpha-particles have discrete kinetic energy levels
2. Beta-particles have a continuous range of kinetic energies
3. Gamma-ray photons have discrete kinetic energy levels

These observations directly relate to two important discoveries; the use of emission spectra to identify elements and the existence of the neutrino.

Which row correctly identifies the observations that lead researchers to the discovery of emission spectra and the existence of the neutrino?

The best estimate of the radii of nuclei is determined from experiments involving

A radioactive sample of initial activity 10.0 Bq has a half-life of 1.0 day. Which value represents the most likely activity after 2.5 days?

A pure sample of a radioactive nuclide has mass m, half-life T_1/2 and initial activity A₀.

Identify the half-life and initial activity of another sample which is otherwise identical but has mass 3m.

	Half-life	Initial activity
A.
B.
C.
D.