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Other Functions




From the previous derivation we ended with the mass-time relation:
[Graphics:Images/index_gr_46.gif]
Using this relation, we can construct further relations--all of which are quite simple. First we start with the luminosity-time relation.




Luminosity-Time Relation


To begin with we state the definition of the luminosity of a black hole:
[Graphics:Images/index_gr_47.gif]
By simply plugging in the mass-time relation for the value of M we get a luminosity-time relation.
[Graphics:Images/index_gr_48.gif]
By simply plugging in all constants we then get the luminosity as a function of time
[Graphics:Images/index_gr_49.gif]






Energy-Time Relation

We can also derive an energy-time function where the E is the energy released by the blackhole.

To begin, we know the relation that
[Graphics:Images/index_gr_56.gif]
Where L is a function defined by
[Graphics:Images/index_gr_57.gif]
To simplify we can rewrite the constant as K
[Graphics:Images/index_gr_58.gif]
Thus providing us with
[Graphics:Images/index_gr_59.gif]
Pulling out the constant yields
[Graphics:Images/index_gr_60.gif]
And taking the derivative gives us
[Graphics:Images/index_gr_61.gif]
Reducing to
[Graphics:Images/index_gr_62.gif]
But we take away the negative sign because we know that this energy is the energy released by the blackhole. Plugging in K finally gives us
[Graphics:Images/index_gr_63.gif]






Temperature-Time Relation


We can state the definition of the temperature of the radiation of a blackhole
[Graphics:Images/index_gr_50.gif]
Plug in the function describing the mass of the blackhole
[Graphics:Images/index_gr_51.gif]
Then plug in constants and reduce to form
[Graphics:Images/index_gr_52.gif]







Radius-Time Relation


Stating the Schwarzchild Radius gives
[Graphics:Images/index_gr_53.gif]
Input the mass as a function of time
[Graphics:Images/index_gr_54.gif]
Then reduce constants and obtain the relation
[Graphics:Images/index_gr_55.gif]






Hawking Radiation | Derivation | Mass as a Function | Other Functions | Analysis of Functions | Exercise | Homework Problems | Great Links

Copyright 2002 by Michael Stroh