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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


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.


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.


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144.

The series corresponding to minimum wavelength transition in H-atom

  • Balmer series

  • Lyman series

  • Paschen series

  • Brackett series


B.

Lyman series

Lyman series is obtained when an electron jumps to the first orbit (n1 = 1 ) from any outer orbit ( n2 = 2, 3 , 4....)

          1λ = RZ 1n1 2 - 1n2  2

For H,

Z = 1 and R is Rydeberg's constant R = 1.097 × 107 m-1.

In this series, the shortest wavelength or the limit of this series

( For n1 = 1 and  n2 = ∞ ) is = 911 Ao

       


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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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