Atomic and Particle physics

The half-life of a radioactive element is 1 day. The initial number of undecayed atoms in a pure sample of this element is 200.

How many undecoyed atoms are there in the sample after 3 days?

• 0

• 25

• 50

• 100

The existence of atomic energy levels is supported by:

• evidence from emission and absorption spectra.

• the Rutherford-Geiger-Mardsen scattering experiment.

• observations related to the wave nature of light.

• the neutron-to-proton ratio of stable elements.

Which of the following statements about the strong interaction is incorrect?

• It is one of the four known fundamental interactions.

• Its range is approximately 10^-15 m.

• It acts on all particles.

• It is responsible for binding atomic nuclei.

Which of the following properties is affected when a nucleus decays through gamma-decay?

• The proton number of the nucleus

• The charge of the nucleus

• The neutron number of the nucleus

• The energy state of the nucleus

On the graph that shows how average binding energy per nucleon varies with nucleon number, the most stable elements can be found:

• around the minimum point of the graph.

• around the maximum point of the graph.

• near the horizontal axis intercept.

• near the vertical axis intercept.

Particle X decays into particle Y. The mediating particle is the W^{+}+. What particles are emitted?

• A positron and a neutrino

• A positron and an antineutrino

• An electron and a neutrino

• An electron and an antineutrino

Consider the following three particles:

I. Electron

II. Electron neutrino

III. Down quark

Which of these particles experience the electromagnetic force?

• I and II only

• I and III only

• II and III only

• I, II and III

The diagram shows some of the energy levels of an atom.

How many different wavelengths are there in the absorption spectrum of the atom?

• 4

• 5

• 10

• 16

The Higgs Boson:

• is a gauge boson.

• is negatively charged.

• has no mass.

• is part of the Standard Model.

The graph shows how the average binding energy per nucleon, A, varies with the atomic number, Z.

Which of the following statements are correct?

I. The most stable elements are found around the maximum point of the graph.

II. Larger Z means more energy is needed to disassemble the given nucleus

III. Total binding energy is proportional to the atomic number

• I and II only

• I and III only

• II and III only

• I, II and III