What is the force that keeps a main sequence star from blowing ...

[Haya94]

What is the force that keeps a main sequence star from blowing apart?
 
  A) magnetism
  B) gravitation
  C) the strong force
  D) radiation pressure
  E) electron degeneration pressure

Question 2

Define absorption and emission lines.
 
  What will be an ideal response?

[coyin]

Answer to Question 1

B

Answer to Question 2

Absorption: When light from a continuous source, such as the dense photosphere of a star, is passed though a thin, cool gas, certain energies from the continuum are absorbed, depending on which elements are present, creating a pattern of dark lines which identify the elements and molecules present in the cool gas cloud. Emission: A hot, thin gas cools off by emitting photons, but only at discrete wavelengths determined by the electron transitions downward of the component atoms. These appear as a pattern of bright emission lines.

[Haya94]

Thanks for the timely response, appreciate it

[peter]

Excellent