Briefly explain why spectral lines are useful in determining the ...

[Mr. Wonderful]

Briefly explain why spectral lines are useful in determining the temperature of their source.
 
  What will be an ideal response?

Question 2

In principle, if we could see all the way to the cosmological horizon we could see the Big Bang taking place. However, our view is blocked for times prior to about 380,000 years after the Big Bang. Why?
 
  A) Before that time, the universe was too crowded with stars.
  B) Before that time, the gas in the universe was dense and ionized and therefore did not allow light to travel freely.
  C) Before that time, the universe was dark so there was no light to illuminate anything.
  D) 380,000 years after the Big Bang marks the time when stars were first born, and thus began to shine the light by which we can see the universe.

[dantucker]

Answer to Question 1

Different ionization states of the same element have different sets of spectral lines. Thus, we can identify the ionization state, which tells us about the temperature because higher temperatures are required to reach higher ionization states.

Answer to Question 2

B

[Mr. Wonderful]

Gracias!

[yeungji]

Excellent