Interaction called the quark interaction.
(e) Nucleons are composed of quarks.
Section 32.7 Cosmology
56. Astronomers studying the light from calcium atoms located in a galaxy in the constellation Boötes find that the spectral lines are shifted toward the red end of the spectrum. The redshift indicates that the galaxy is moving away at a speed of 3.9 106 m/s. What is the distance (in light years) to the galaxy?
(a) 4.7 109 light years (c) 1.1 107 light years (e) 6.6 104 light years
(b) 2.3 108 light years (d) 8.4 106 light years
57. Which one of the following statements concerning the standard cosmological model is false?
(a) Shortly after the Big Bang, all of the fundamental forces behaved as a single force.
(b) About 0.5 million years after the Big Bang, hydrogen and helium atoms began to form.
(c) The first distinguishable particles in existence after the Big Bang were quarks and leptons.
(d) The Grand Unified Theory describes the universe immediately before and shortly after the
Big Bang.
(e) At 1043 s after the Big Bang, the gravitational force was distinguishable from the other fundamental forces.
Additional Problems
58. Nucleus A has Z protons and N neutrons. Nucleus B has 2Z protons and 2N neutrons. Nucleus A has a smaller binding energy per nucleon than B. Which entry in the table below is correct?
The fusion of two A's to form B The fission of B to form two A's
(a) process releases energy process absorbs energy
(b) process absorbs energy process absorbs energy
(c) process releases energy process releases energy
(d) process absorbs energy process releases energy
(e) process is not possible process releases energy
59. Consider the nuclear reaction
and the masses:
= 235.0439 u;
= 93.9063 u; n = 1.008 67 u. If 208.66 MeV of energy is released in
this reaction, determine the mass of X.
(a) 38.970 u (c) 40.962 u (e) 139.905 u
(b) 39.962 u (d) 84.589 u