Physics Exam (Chapter 9)

13 cards


 
  
Created Apr 22, 2013
by
PhysicsStar

 

 
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1
What is the composition of the interstellar medium
 
about 75% hydrogen, 25% helium, 1% interstellar dust, with traces of heavier elements
2
How is a nebula different from the interstellar medium
 
A nebula can be seen with visible light
3
Why are these clouds of interstellar media stable
 
Gas pressure outward balances gravity inward. Turbulence and magnetic elds also help gas...
4
What is the source of energy in a protostar
 
Gravitational potential energy is transformed into heat as the protostar contracts
5
What forces are in balance in a star on the main sequence
 
Gas pressure outward balances gravity inward
6
What factors do gas pressure and gravity depend on
 
Gas pressure depends on temperature, which in turn, depends on the rate of nuclear fusion...
7
What are the characteristics of a main sequence star
 
(a) It's the earliest stage of a star's life. (b) It is still contracting and heating...
8
What is the proton-proton chain? What type of nuclear reaction is it
 
4 protons fuse together to form helium and energy. Nuclear fusion
9
What is the difference between the proton-proton chain and nuclear fission
 
The proton-proton chain takes the smaller hydrogen nuclei and fuses them together to form...
10
Where does the energy come from in the proton-proton chain
 
The mass of a helium nucleus is smaller than the masses of the hydrogen nuclei that are fused...
11
What is the CNO cycle
 
The CNO cycle is a nuclear fusion cycle involving carbon, nitrogen, and oxygen. It is a...
12
Why does the CNO cycle require a higher temperature than the proton-proton chain
 
There are more protons in the carbon, nitrogen, and oxygen nuclei than in hydrogen nuclei...
13
State the mass-luminosity relation
 
The more massive a star is, the more luminous it is because more mass leads to more gravity....


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