Nuclear Physics (DP IB Physics: HL)

Two elements are compared where the nucleus of the first element, N₁ has radius r and nucleon number Z, and the nucleus of the second element N₂ has radius 3r and nucleon number   Z. What is the ratio of  ?

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.

A radioactive source X consists of 10.4 × 10¹¹ atoms of a nuclide of half-life 5 days. A second source Y consists of 5.2 × 10¹⁰ atoms of another nuclide of half-life 6 days.

After how many days will the number of radioactive atoms in X be equal to Y?

Two radioactive elements X and Y have half–lives T_X and T_Y respectively. Initially samples of S, N_X contains three times as many atoms of Y, N_Y .

After a certain time t, which of the expressions for  is correct?

The initial activity of a radioactive source is 160 counts per second. After a time T, its activity becomes 5 counts per second.

 If the half–life of the source is 18 hours, what is T?

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.

Alpha particles with various energy E are directed at a nuclei with atomic number Z. Small deviations from the predictions of the Rutherford scattering model are observed.

Which value of E and Z is most likely to result in the greatest deviations from the Rutherford scattering model?

Two radioactive nuclides, P and Q, have half-lives of 70 s and 175 s respectively. At time t = 0, samples of P and Q contain the same number of nuclei.

What is when t = 350 s?

The diameter of Iridium-192 () nucleus is approximately four times that of the diameter of a nucleus of which other isotope?

Two unstable isotopes are initially present in equal numbers. Isotope Y has a half life of 6 minutes and isotope Z has a half life of 3 minutes. Which expression correctly describes the ratio of the activity of Y to Z after 12 minutes?

The ratio is equal to 1.2 where the nucleus of X is .

How many nucleons does nucleus Y have?

A pure sample of a known element has a very short half-life. What measurement(s), together with the initial activity of the sample, must be made in order to measure the half-life of the element?