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...
de Broglie hypothesis According to de-Broglie, a wave is always associated with every moving particle. This wave is known as de-Broglie wave or matter wave. It means a matter wave have particle nature as well as wave nature i.e., dual nature. From quantum theory of radiation, energy of photon, E = h๐, where ๐ = frequency of incident photon . From Einstein’s theory of relativity E = √(m 0 2 c 4 + p 2 c 2 ) If m 0 = 0, then E = pc, p = momentum and c = velocity of light Now E = h๐ and E = pc ∴ h๐ = pc or p = h๐/c ∵ c = ๐ฮป or ฮป = c/๐ ∴ p = h/ฮป or ฮป = h/p This is known as de-Broglie wavelength This wavelength is always associated with a photon Since momentum is the characteristic of particles, and the wavelength is characteristic o...