Which Formulas Solve These Physics Problems?

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SUMMARY

The discussion focuses on two physics problems involving the application of specific formulas. For the first problem regarding a protostar with a temperature of 2500K, the relevant formula is Wien's Law, which states that the wavelength at which radiation is maximized (lambda max) is inversely proportional to temperature (lambda max = 1/T). The second problem involves calculating the observed wavelength of light from a galaxy moving away from Earth at 1.3 x 108 m/s, where the Doppler shift formula is applicable to determine the redshift effect on the emitted wavelength of 450nm.

PREREQUISITES
  • Understanding of Wien's Law in thermodynamics
  • Familiarity with the Doppler shift formula in astrophysics
  • Basic knowledge of wavelength and frequency relationships
  • Concept of redshift in cosmology
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  • Study Wien's Law and its applications in astrophysics
  • Learn the Doppler shift formula and its implications for light from moving objects
  • Explore the relationship between temperature and radiation in blackbody physics
  • Investigate redshift calculations and their significance in cosmology
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Students in introductory physics courses, astrophysics enthusiasts, and anyone interested in understanding the principles of light behavior in relation to temperature and motion.

zoiberg137
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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 wavelength 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!
 
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zoiberg137 said:
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?
 

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