Question

In the movie, The Avengers, Loki's scepter contained one of the six infinity stones - the Mind Stone. Although the Mind Stone appears blue while in the scepter, it actually emits light in the yellow part of the visible spectrum, as well as low-energy gamma rays. It was these gamma rays that allowed Dr. Banner to track Loki back to New York City, where the movie?s epic final battle took place. Presumably, the Mind Stone was formed at the beginning of the Universe during the Big Bang, but the elemental source of its gamma rays is unknown. The element does, however, have a very long half-life (5.76 billion years, or 5.76E9 years). If the Mind Stone originally contained 7.52E24 atoms of the unknown element when it formed during the Big Bang, how many atoms does it contain now, 13.8 billion years later (13.8E9 years)?

1.43E24 atoms

9.96E23 atoms

2.14E24 atoms

3.65E24 atoms

1.87E24 atoms

Question 20

When a U-238 atom undergoes alpha decay, which of the following is the daughter nucleus?

U-235

Th-238

Th-234

Pa-231

Rn-222

Question 21

A Au-197 atom (gold-197) contains 79 protons in its nucleus. Determine the number of neutrons in its nucleus and then calculate the nuclear binding energy per nucleon for Au-197. The atomic mass of Au-197 is 196.966540 u.

7.92 MeV

1560 MeV

13.2 MeV

19.7 MeV

5.21 MeV

Question 22

What is the DeBroglie wavelength of an electron with a kinetic energy of 6.7 eV?

2.95E-12 m

4.74E-10 m

1.98E-3 m

1.10E-9 m

4.36E-12 m

Answer 1

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