Hydrogen atoms are excited from ground state of the principal quantum number 4. Then, the number of spectral lines observed will be

(a) 3                                     (b) 6

(c) 5                                     (d) 2

Concept Questions :-

Spectral series
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When electron jumps from n = 4 to n = 2 orbit, we get [2000]

(1) second line of Lyman series

(2) second line of Balmer series

(3) second line of Paschen series

(4) an absorption line of Balmer series

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Spectral series
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The spectrum obtained from a sodium vapour lamp is an example of

(a) band spectrum

(b) continuous spectrum

(c) emission spectrum

(d) absorption spectrum

Concept Questions :-

Spectral series
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The radius of hydrogen atom in its ground state is 5.3×10-11 m. After collision with an electron it is found to have a radius of 21.2 ×10-11 m. What is the principal quantum number n of the final state of the atom? [1994]

(1) n = 4            (2) n = 2            (3) n = 16            (4) n = 3

Concept Questions :-

Bohr's model of atom
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In terms of Bohr radius a0, the radius of the second Bohr orbit of a hydrogen atom is given by [1992]

(1) 4a0              (2) 8a0           (3) 2a0              (4) 2a0

Concept Questions :-

Bohr's model of atom
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The energy of lowest state of hydrogen is -13.6 eV. The ionisation energy of first excited state will be

1. 13.6 eV                             2. 4.2 eV

3. 6.8 eV                               4. 3.4 eV

Concept Questions :-

Bohr's model of atom
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 An x-ray tube is operating at 30 kV then the minimum wavelength of the x-rays coming out of the tube is:

(1) 1.24 A0          (2) 0.413 A0             (3) 0.124 A0             (4) 0.13 A0

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A diatomic molecule is made of two masses m1 and m2 which are separated by a distance r.  If we calculate its rotational energy by applying Bohr's rule of angular momentum quantization, its energy will be given by (n is an integer):

(1) m1+m22n2h22m12m22r2                   (2) n2h22π2(m1+m2)r2

(3) 2n2h2(m1+m2)r2                           (4) m1+m2n2h28π2m1m2r2

Concept Questions :-

Bohr's model of atom
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In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change ?

(A) From n = 2 to n = 1

(B) From n = 3 to n = 1

(C) From n = 4 to n = 2

(D) From  n = 3 to n = 2

Concept Questions :-

Bohr's model of atom
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In the Bohr's hydrogen atom model, the radius of the stationary orbit is directly proportional to (n = principal quantum number) [CBSE PMT 1996; AIIMS 199; DCE 2002; AMU (med.) 2010)

(1) n-1        (2) n            (3) n-2         (4) n2

Concept Questions :-

Bohr's model of atom
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