Question

choose A B C D

QUESTION 1

1. Star formation in giant gas clouds is a result of competition between which forces?

   		Light and rotation
   		Light and dark
   		Rotation and gas pressure
   		Gravity and gas pressure

10 points   

QUESTION 2

1. What effect sets the largest size a star can have?

   		The forming star is shining so strongly that it blows the collapsing gas cloud apart.
   		If the star was any larger it would instantly form a Black Hole.
   		If the star was any larger it would instantly explode as a Supernova.
   		The degeneracy pressure of the electrons stops the star from growing any larger.

10 points   

QUESTION 3

1. What answer most accurately describes the end life of a star 8-20 times more massive than our Sun?

   		The star expands to become a Red Giant, leaving behind a White Dwarf which then quietly cools and fades.
   		Deep in the star's core, elements fuse into ever heavier elements until no more energy is available to hold itself up against gravity; the star explodes as a Supernovae and the core is crushed into a Neutron Star.
   		The massive star fuses all the hydrogen to helium and can no longer hold itself up against its own gravity, ultimately collapsing into a Black Hole.
   		The massive star sheds off its outer layers, leaving behind no trace, other than an expanding planetary nebular.

10 points   

QUESTION 4

1. What happens in the core of a star fusing helium into carbon after all the helium is used up in the reaction?

   		There is an helium flash that indicates the termination of helium fusion in the core, and the star becomes very luminous and expands rapidly for a brief moment.
   		The carbon fusion takes over helium fusion in the core and the stellar structure remains stable. Helium starts fusion in a shell.
   		Energy generation through fusion stops because carbon fusion requires higher temperature. The core collapses and helium starts fusing in shell.
   		Energy generation through fusion stops because carbon fusion requires higher temperature. The core expands and cools off.

Answer 1

and gos pressure -1 Toto gravity 2A 3- 10 - wc