Question

The hydrogenlike elements (valence +1) exhibit a splitting of the energy states without an external magnetic field; this is due to (A) the interaction of the spin and orbital angular momentum. (B) the penetration of the electron into the inert core of filled subshells. (C) the fact that in a downward transition the orbital angular momentum must change by one. (D) the requirement that no two electrons be in the same state at the same time. (E) none of these.

The cross section of a nuclear reaction is (A) directly proportional to both the flux and the energy of the incident particle. (B) independent of the incident particle but highly dependent on the target nuclei. (C) dependent on the particular reaction being considered and the energy of the incident particle. (D) influenced by the Coulomb force but is independent of the type of target nuclei and reaction. (E) applicable only to neutron-induced reactions.

Forces between electrons or positrons and nucleons that result in beta decay are best understood in terms of (A) the strong nuclear (hadronic) interaction. (B) the electromagnetic interaction. (C) the weak nuclear interaction. (D) the gravitational interaction. (E) none of these

In quantum electrodynamics (QED), the electromagnetic field is described in terms of (A) the interaction of electrons. (B) hadrons. (C) action at a distance. (D) the weak nuclear interaction. (E) the interaction of photons.

What are the rules for combining color? (A) All hadrons are colorless (or white). (B) baryons are colorless, but mesons can have net color (C) mesons are colorless, but baryons can have net color (D) both mesons and baryons can have net color (E) none of the above

Answer 1

A) The splitting of enrgy states without external magnetic field (Fine soectrum) is due to

A. The interaction of spin and angular momentum

reason: The spin S of the electron interacts with the magnetic field produced by the orbital motion L of the electron itself. The potential energy given by:

the energy shifts can be calculated using this interaction term.

B) The nuclear cross section is indeendent of incident particles but is highly dependent on target nuclei.

is the cross section

no of projectile nuclei absorbed per unit time

N is the no of atoms contained in foil (target)

is the transmitted intensity

C) Beta decay is weak nuclear interaction that converts atomic nucleus into nucleus with atomic number decreased by one while emitting a positron and electron neutrino in case of beta plus. Ex

D) As particles like electrons and protons can interact as fields the electro magnetic fields can interact as particle like quanta which we call photons. Thus it is the interaction of photons ( quanta).

E,) All hadrons are colorless.

Baryons are made of three different quarks of different colors resulting in net white color ans mesons are composed of quark and anti quark canceling their colors.