Advertisements
Advertisements
प्रश्न
An atom is in its excited state. Does the probability of its coming to ground state depend on whether the radiation is already present or not? If yes, does it also depend on the wavelength of the radiation present?
Advertisements
उत्तर
When an atom transits from an excited state to ground state in the presence of an external radiation then it is called as stimulated transition.
When an atom transits from an excited state to ground state on its own then it is called as spontaneous transition.
Ratio of the coefficient for stimulated transition to spontaneous transition is given by
`R = A/(Bp(v)) = e^{(hv)/(kr)} - 1`
For microwave region
`v = 10^10 (say)`
`R =e ^(( 6.6 xx 10^-34xx10^10)/(1.38xx10^-23xx300)) -1`
`=e^0.0016 -1`
This implies that stimulated transition dominate in this region.
For visible region
`V = 10^15`
`rArr R = e^160 - 1`
⇒ R >> 1
So here spontaneous transition dominate.
APPEARS IN
संबंधित प्रश्न
How many wavelengths are emitted by atomic hydrogen in visible range (380 nm − 780 nm)? In the range 50 nm to 100 nm?
Three photons coming from excited atomic-hydrogen sample are picked up. Their energies are 12.1 eV, 10.2 eV and 1.9 eV. These photons must come from
The energy of an atom (or ion) in its ground state is −54.4 eV. It may be
How long can an electric lamp of 100 W be kept glowing by fusion of 2 kg of deuterium? Take the fusion reaction as
\[\ce{^2_1H + ^2_1H -> ^3_2He + n + 3.27 MeV}\]
Why must an atom also contain positive charge?
How is the positive charge distributed in J. J. Thomson's model of the atom?
What did later studies show about the distribution of electrons and positive charge in Thomson's model?
How does the spectrum of light emitted from rarefied gases appear?
Why can radiation emitted by rarefied gases be considered to arise from individual atoms?
What was established about each element's radiation spectrum in the early nineteenth century?
What characterises the set of lines that hydrogen always gives?
Why is the spectrum of hydrogen considered in detail?
With whom did Ernst Rutherford create the modern theory of radioactivity?
What did Rutherford discover by scattering alpha rays off metal foils?
Of whom had Ernst Rutherford earlier been a research student?
What did Rutherford propose in 1906 to investigate atomic structure?
Who carried out Rutherford's proposed alpha-particle scattering experiment around 1911?
What model resulted from the explanation of the alpha-particle scattering results?
