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National Bird Day: Why Birds Matter to Us

National Bird Day is celebrated every year on 5 January . This day is observed to spread awareness about birds, their importance in nature, and the need to protect them. Birds are beautiful living beings and play a very important role in keeping our environment healthy. Origin of National Bird Day National Bird Day was first celebrated in the year 2002 . It was started by bird lovers and environmental groups to protect birds from dangers like deforestation, pollution, and illegal hunting. The main aim of this day is to teach people, especially students, why birds are important and how we can help save them. Why Is National Bird Day Celebrated Every Year? National Bird Day is celebrated every year because many bird species are disappearing due to human activities. Cutting trees, using plastic, pollution, and climate change are harming birds and their homes. This day reminds us that: Birds need protection Nature should be respected Everyone has a responsibil...
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Planck's Radiation Law | Planck's radiation formula

Planck's Radiation Law

  • This is application of Bose-Einstein statistics.
  • According to quantum theory, the radiant energy occurs in energy packets.
  • These packets are known as quanta or photon.
  • The energy of packet should be h times the frequency of photon.
  • The momentum of each packet should be h/c times the frequency of photon.
  • The photons are indistinguishable particles having zero rest mass and having spin quantum number 1.
  • Thus photons are Bose particle and hence Bose Einstein statistics can be applied on it.
  • By using Planck's radiation law, we can also establish the Rayleigh Jean’s law, Wein’s law and Stefan-Boltzmann’s law.

Planck's radiation law

  • According to Planck, the energy density of radiations emitted from a black body in the wavelength range λ and λ + dλ is, uλ dλ = (Nλ dλ) E 
  • Here Nλ dλ = Number of oscillators (number of modes of vibration) in the wavelength range λ and λ + dλ
  • E is average energy of Planck's oscillator.
Since
Therefore
This is Planck’s radiation formula in terms of wavelength 

Since
Therefore
This is Planck’s radiation formula in terms of frequency

To know more about this lecture you can visit https://youtu.be/UHW5KkQMUpE
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