A 14.4 KeV photon from 57 Fe is red shifted as it rises from a sourceat ground level to an absorber placed at the top of a tower of a height of 20 m because it has to expend energy to climb the gravitational potential. Derive an expression for thered shift as a fraction of the energy of the photon. What velocity of the absorber foil would be needed to compensate redshift and in which direction?(adsbygoogle = window.adsbygoogle || []).push({});

so first i found the formula f/fo = sqrt(1-b/1+b)

and to find the velocity v = bc where c is the speed of light.

so basically the natural frequency fo is related to the energy of the photon which is 14.4 KeV.

But I need to find the other frequency in order to solve for Beta and thus find the velocity. I do NOT know how to do this.

There must be a formula relating the height to the enrgy or to the frequency.

And for the second part i said: since it is redshifted we have an increase in the wavelength thus a decrease in energy and decrease in velocity.

So it is in the opposite direction of the source.

Is it right?

It's urgent :)

Thanks for any help :)

Joe

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# Homework Help: Red shift and velocity

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