How Do I Solve These Problems?

  • Thread starter zoiberg137
  • Start date
  • #1
28
0
I've memorized all the formulas I need for my first intro to physics class...But I am still trying to get familiar with what formula to use for what problem. Here are two questions. If someone could tell me what formula i would use to solve them, that would be great!!

1. At what rate does a protostar with a temperature of 2500k radiate most strongly?

(I'm thinking that we would want to use weins laws that states lambda max is equal to 1/temp. But 1/2500k does not give me a wavelength....)





2. In a far away galaxy, light is emitted with an average wavelength of 450nm. If this galaxy is moving away from earth at a rate of 1.3*E8 m/s, what wavelength of light will we see?

(So if its moving away that tells us that it will be a redshift...But how do we get the exact wavelength? I'm thinking that we would divide the recessional velocity of 1.3*E8 by our constant 3*E8, which would give us 2.31m. And then we would say that our

change in wavelnth/true wavelenght of 450 = to 2.31 m/s

Am I on the right track here? This gives me 1038, but I'm guessing I need to convert one of these two first. Or maybe I'm doing this completely wrong....)



P.S.-You people have been awesome with your previous help. I hope that one day I am able to answer peoples questions!
 

Answers and Replies

  • #2
6,054
391
1. At what rate does a protostar with a temperature of 2500k radiate most strongly?

(I'm thinking that we would want to use weins laws that states lambda max is equal to 1/temp. But 1/2500k does not give me a wavelength....)

It may be just me, but the question is meaningless. One could ask just at what rate a protostar with a given temperature radiates, but "most strongly" makes this incomprehensible.

2. In a far away galaxy, light is emitted with an average wavelength of 450nm. If this galaxy is moving away from earth at a rate of 1.3*E8 m/s, what wavelength of light will we see?

What is the Doppler shift formula?
 

Related Threads on How Do I Solve These Problems?

Replies
8
Views
941
Replies
6
Views
1K
Replies
19
Views
2K
  • Last Post
Replies
1
Views
1K
Replies
3
Views
1K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
2
Views
922
  • Last Post
Replies
15
Views
2K
Replies
4
Views
2K
Top