The strong nuclear force

In β − decay:

Which nuclear change results in the nucleus with the greatest specific charge?

Two stable isotopes of helium are 42He and 32He.

An atom of 42He is produced in a rock that contains uranium. It is produced following 238 the radioactive decay of a 92U atom. The decay also creates an atom of thorium (Th).

238 Write an equation for the decay of 92U.

238

A 32He nucleus can be produced by the decay of a tritium nucleus 31H.

State and explain which exchange particle is responsible for this decay.

Helium was discovered by analysing the light in the absorption spectrum of the Sun.

Figure 1 shows the positions of the brightest lines, labelled A to F, in the emission spectrum of helium. The brightest lines in the emission spectra of sodium and hydrogen are also shown.

Before helium was identified, some scientists suggested that the lines of the helium spectrum seen in the absorption spectrum of the Sun were due to the presence of sodium and hydrogen.

Discuss, with reference to the lines A to F in Figure 1, the evidence for and against this suggestion.

Calculate, in eV, the change in energy level responsible for the spectral line labelled in Figure 1.

Explain, with reference to the processes within an atom, the difference between an emission spectrum and an absorption spectrum.

Carbon-14 d ys into nitrogen-14 with the release of a beta (β⁻) particle and an

State the change of quark character in β⁻ decay.

Figure 2 shows the distribution of kinetic energies of β⁻ particles from the decay of carbon-14.

Explain how Figure 2 supports the existence of the antineutrino.

The existence of the antineutrino was confirmed by experiments in which antineutrinos interact with protons. The equation for this interaction is:

Identify particle X.

The positron released in this interaction is annihilated when it encounters an electron. A pair of gamma photons is then produced. Particle X can be absorbed by a nucleus. This produces another gamma ray. Table 1 contains data for three gamma photons detected during an antineutrino–proton interaction experiment.

Deduce which of the three gamma photons could have been produced by positron annihilation.

Which row describes the variation with distance of the strong nuclear force?

The proton number of uranium is 92 and the proton number of radon is 88

Which series of decays turns a uranium nucleus into a radon nucleus?

232 − The radioactive nuclide 90Th decays by one α emission followed by two β emissions.

Which nuclide is formed as a result of these decays?

125 131 Two isotopes of iodine are I and I. 53 53

Determine, for these two isotopes, the difference between the constituents of the nuclei.

131 – A₅₃ I nuclide undergoes beta (β) decay to form a xenon nuclide.

State the nucleon number of the xenon nuclide.

125 A₅₃ I nuclide decays by electron capture to form a tellurium nuclide.

State two differences between the constituents of the iodine nucleus and the tellurium nucleus it decays into.

Internal conversion is a process in which a nucleus in an excited state can release its excess energy. In internal conversion all of the excess energy is transferred from the nucleus to an orbital electron through the electromagnetic force. This orbital electron is ejected from the atom.

The tellurium nucleus formed in question 01.3 is in an excited state and can undergo internal conversion.

Discuss three differences between internal conversion and beta (β^–) decay.

The process of beta plus (β⁺) decay can be represented by

Which row identifies particles X and Y ?

The decay is represented by this equation:

Complete the equation to show the decay by filling in the gaps.

Explain which fundamental interaction is responsible for the decay in question 01.1.

One decay mechanism for the decay of results in the argon nucleus having an excess energy of 1.46 MeV. It loses this energy by emitting a single gamma photon.

Calculate the wavelength of the photon released by the argon nucleus.

The potassium isotope can also decay by a second decay process to form a

Suggest how the emissions from a nucleus of decaying potassium can be used to confirm which decay process is occurring.