Fundamental forces in nature.

1. Describe two of the four fundamental forces in nature.
2. Explain why there is a maximum in the binding energy curve. What element is most
   stable?
3. Fusion is a common process in stars. If a star is massive enough reaction of the
   following type can occur:
   6� 12 + 6� 12 → �
   1 + �
   Determine the number of protons, neutrons, and the nucleon number of the element X
   (Periodic Table is attached).
4. Explain how giants and supergiants can have a low surface temperature but still have a
   high luminosity.

Sample Solution