Rayleigh Jeans Law Video Lecture - Civil Engineering (CE)

we shall prove the religions flowform
plunks law for this we shall take the
plank slow fast and the Planck's law is
you lambda D lambda equal to 8 pi HC by
lambda to the power 5 into 1 by e to the
power a C by lambda KT minus 1 into D
lambda from this we have to prove the
religious law which is 8 pi KT by lambda
to the power 5 to the 4 sorry lambda
therefore D lambda equal to e lambda D
lambda this is the religious law and we
have to prove this from this plants law
for this we have to first expand is the
exponential part of the Planck's law
for this it will be
after expending these will be like one
plus HC by lambda Q T plus dot dot dot
the higher order terms that equals minus
1 and this is 38 by HC by lambda to the
power 5 to this is the higher order
terms of the expansion
the plus and minus one canceled out each
other and the remain HC by lambda K T
plus the higher order comes
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now note that in the religions flow
which is only valid for the whole value
of lambda I mean we've lengthened is
very very greater than 1 and lambda is
high if lambda is high then lambda T is
also high so 1 by lambda T is low that
is HC by lambda T K that's low so we can
vanish the high order terms of a civil
aMDA key as it tends to 0 so we vanish
it or omit it
the higher order terms of the expansion
after that it will be like a to HC by
lambda there 5 into 1 by HC by lambda KT
this is equal to 8 by HC by lambda to
the power 5 - I am de KT by H the left
here there will be D lambda sorry
ACH canceled out and remain lambda to
the power 4 D lambda and this is the
so-called religions law which we have to
prove from Planck's law this is the
religion slow this is the process to
prepare a legend slow from the plants
law