Advertisements
Advertisements
प्रश्न
State Bohr’s postulate of hydrogen atom which successfully explains the emission lines in the spectrum of hydrogen atom. Use Rydberg formula to determine the wavelength of Hα line. [Given: Rydberg constant R = 1.03 × 107 m−1]
Advertisements
उत्तर
Bohr’s third postulate successfully explains emission lines. It states that ‘Whenever an electron jumps from one of its specified non-radiating orbit to another such orbit, it emits or absorbs a photon whose energy is equal to the energy difference between the initial and final states’.
Thus,
`E_1-E_t=hv=(hc)/lambda`
The Rydberg formula for the Balmer series is given as
`1/lambda=R(1/n_t^2-1/n_1^2)`
‘R’ is a constant called the Rydberg constant and its value is 1.03 × 107 m−1.
The Hα-line of the Balmer series is obtained when an electron jumps to the second orbit (nf = 2) from the third orbit (ni = 3).
`1/lambda=1.03xx10^7(1/2^2-1/3^3)`
`1/lambda=1.03xx10^7(1/4-1/9)`
`1/lambda=1.03xx10^7((9-4)/(9xx4))`
`1/lambda=1.03xx10^7(5/36)`
`lambda=36/(5xx1.03xx10^7)`
λ = 6.99 x 10-7
λ = 699 x 10-2 x 10-7
λ = 699 nm
The value of λ lies in the visible region.
APPEARS IN
संबंधित प्रश्न
The longest wavelength doublet absorption transition is observed at 589 and 589.6 nm. Calculate the frequency of each transition and energy difference between two excited states.
if `E_p` and `E_k` represent potential energy and kinetic energy respectively, of an orbital electron, then, according to B9hr's theory:
a)`E_k = -E_p"/"2`
b) `E_k = -E_p`
c) `E_k = -2E_p`
d) `E_k = 2E_p`
The difference in the frequencies of series limit of Lyman series and Balmer series is equal to the frequency of the first line of the Lyman series. Explain.
When a photon stimulates the emission of another photon, the two photons have
(a) same energy
(b) same direction
(c) same phase
(d) same wavelength
When a photon is emitted by a hydrogen atom, the photon carries a momentum with it. (a) Calculate the momentum carries by the photon when a hydrogen atom emits light of wavelength 656.3 nm. (b) With what speed does the atom recoil during this transition? Take the mass of the hydrogen atom = 1.67 × 10−27 kg. (c) Find the kinetic energy of recoil of the atom.
According to Bohr, 'Angular momentum of an orbiting electron is quantized'. What is meant by this statement?
How are various lines of Lyman series formed? Explain on the basis of Bohr’s theory.
According to Bohr's model of hydrogen atom, an electron can revolve round a proton indefinitely, if its path is ______.
For the ground state, the electron in the H-atom has an angular momentum = h, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true ______.
In Bohr's theory of hydrogen atom, the electron jumps from higher orbit n to lower orbit p. The wavelength will be minimum for the transition ______.
