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 Multiple Choice QuestionsMultiple Choice Questions

141.

Total energy of the electron in hydrogen atom above 0 eV leads to

  • continuation of energy states

  • large number of discrete ionised states

  • balmer series

  • paschen series


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142.

Assertion:  Bohr's atomic model cannot be used to explain multiple electron species.

Reason: It does not take inter-electronic interactions in account.

  • If both assertion and reason are true and reason
    is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion.

Electroms with more than one atom, such as Helium (He), and Nitrogen ( N ) etc are referred  as multi-electron atoms

The Bohr model works only for hydrogen because it considers only the interactions between one electron and the nucleus. The Bohr model is based on the energy levels of one electron orbiting a nucleus at various energy levels.


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143.

Assertion: Total energy of electron in an hydrogen atom is negative.

Reason: It is bounded to the nucleus.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


144.

The series corresponding to minimum wavelength transition in H-atom

  • Balmer series

  • Lyman series

  • Paschen series

  • Brackett series


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145.

What would be maximum wavelength for Brackett series of hydrogen-spectrum?

  • 74589 Ao

  • 22790 Ao

  • 40519 Ao

  • 18753 Ao


146.

What would be the radius of second orbit of  He+  ion?

  • 1.508 Ao

  • 3.023 Ao

  • 2.068 Ao

  • 4.458 Ao


147.

The wavelength of Lyrnen series for first number
is

  • 4 × 1.097 × 1073 m

  • 34 × 1.097 × 107 m

  • 43 × 1.097 × 107 m

  • 34× 1.097 × 107


148.

The wavelengths of Kα  X- rays for lead isotopes  Pb208 , Pb206  and  Pb204 are  λ1, λ2 and  λ3 respectively. Then

  • λ2λ1 λ3

  • λ2 = λ1 + λ3

  • λ2 = λ1 λ2

  • λ=  λ1λ3


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149.

Assertion:  It is essential that all the lines available in the emission spectrum will also be available in the absorption spectrum.

Reason: The spectrum of hydrogen atom is only absorption spectrum.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


150.

What is the energy of He+ electron in first orbit?

  • 40.8 eV

  • -27.2 eV

  • -54.4 eV

  • -13.6 eV


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