A hydrogen atom is in an excited state of principal quantum number (n), it emits a photon of wavelength (λ) when it returns to the ground state. The value of n is 

(1) λRλR-1                   (2) (λR-1)λR

(3) λ(R-1)                   (4) None of these

Concept Questions :-

Bohr's model of atom
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 Consider an electron in the nth orbit of a hydrogen atom in the Bohr model. The circumference of the orbit can be expressed in terms of the de-Broglie wavelength λ of that electron as:

(1) (0.529) nλ           (2) nλ             (3) (13.6) λ         (4) nλ

Concept Questions :-

Bohr's model of atom
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In the Bohr's model of a hydrogen atom, the centripetal force is furnished by the Coulomb attraction between the proton and the electron.  If α0 is the radius of the ground state orbit, m is the mass and e is the charge on the electron, ε0 is the vaccum permittivity, the speed of the electron is  [1998]

(1) zero          (2) eε0a0m           (3) e4πε0a0m               (4) 4πε0a0me

Concept Questions :-

Bohr's model of atom
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The ground state energy of H-atom is 13.6 eV. The energy needed to ionise H-atom from its second excited state [1991]

(1) 1.51 eV          (2) 3.4 eV            (3) 13.6 eV             (4) 12.1 eV

Concept Questions :-

Bohr's model of atom
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The element which has a ka x-rays line of wavelength 1.8 A0 is (R=1.1×10-7m-1, b=1 and 5/33=0.39)

(1) Co, Z=27      (2) Iron, Z = 26        (3) Mn, Z = 25           (4) Ni, Z = 28

Concept Questions :-

Spectral series
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The given diagram indicates the energy levels of a certain atom. When the system moves from 2E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from 4E3 level to E is

(1) λ3           (2) 3λ4        (3) 4λ3            (4) 3λ

Concept Questions :-

Spectral series
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The wavelength of the first spectral line in the Balmer series of hydrogen atom is 6561 A0. The wavelength of the second spectral line in the Balmer series of singly ionized helium atom is [IIT-JEE 2011]

(1) 1215 A0        (2) 1640 A0            (3) 2430 A0           (4) 4687 A0

Concept Questions :-

Spectral series
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Energy E of a hydrogen atom with principal quantum number n is given by E=-13.6n2eV.  The energy of a photon ejected when the electron jumps from n = 3 state to n = 2 state of hydrogen, is approximately [2004]

(1) 1.5 eV         (2) 0.85 eV          (3) 3.4 eV            (4) 1.9 eV

Concept Questions :-

Bohr's model of atom
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The energy of ground electronic state of hydrogen atom is -13.6 eV.  The energy of the first excited state will be [1997]

(1) -54.4 eV         (2) -27.2 eV           (3) -6.8 eV               (4) -3.4 eV

Concept Questions :-

Bohr's model of atom
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The total energy of an electron in the first excited state of hydrogen is about -3.4 eV. Its kinetic energy in this state is [2005]

(1) -3.4 eV            (2) -6.8 eV             (3) 6.8 eV           (4) 3.4 eV

Concept Questions :-

Bohr's model of atom
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