An ionised \(H\)-molecule consists of an electron and two protons. The protons are separated by a small distance of the order of angstrom. In the ground state:

(a) the electron would not move in circular orbits.
(b) the energy would be \(2^{4}\) times that of a \(H\)-atom.
(c) the electron's orbit would go around the protons.
(d) the molecule will soon decay in a proton and a \(H\)-atom.

1. (a), (b)
2. (a), (c)
3. (b), (c), (d)
4. (c), (d)

Subtopic:  Various Atomic Models |
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The Bohr model for the spectra of a \(H\)-atom:

a. will not apply to hydrogen in the molecular form.
b. will not be applicable as it is for a He-atom.
c. is valid only at room temperature.
d. predicts continuous as well as discrete spectral lines.

1. (a), (b)
2. (c), (d)
3. (b), (c)
4. (a), (d)

Subtopic:  Bohr's Model of Atom |
 57%
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The Balmer series for the H-atom can be observed:
 

a. if we measure the frequencies of light emitted when an excited atom falls to the ground state
b. if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
c. in any transition in a H-atom
d. as a sequence of frequencies with the higher frequencies getting closely packed

1. (b, c)

2. (a, c)

3. (b, d)

4. (c, d)

Subtopic:  Spectral Series |
 63%
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Let En=-18ε02me4n2h2 be the energy of the nth level of H-atom. If all the H-atoms are in the ground state and radiation of frequency (E2-E1)h falls on it,

(a) it will not be absorbed at all
(b) some of the atoms will move to the first excited state
(c) all atoms will be excited to the n = 2 state
(d) no atoms will make a transition to the n = 3 state

1. (b, d)

2. (a, d)

3. (b, c, d)

4. (c, d)

Subtopic:  Bohr's Model of Atom |
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The simple Bohr model is not applicable to He4 atom because

(a) He4 is an inert gas
(b) He4 has neutrons in the nucleus
(c) He4 has one more electron
(d) electrons are not subject to central forces

1. (a, c)

2. (a, c, d)

3. (b, d)

4. (c, d)

Subtopic:  Bohr's Model of Atom |
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The energy of an atom with a K-shell vacancy is EK, that with an L-shell vacancy is EL, and that with an M- shell vacancy is EM: all compared to an atom with no vacancy, then, 
(I) EK < E
(II) EL > EM 
(III) EL - EK \(E_{K\alpha}\), the energy of \(K_\alpha \) photon
1. I is true 
2. I, III are true 
3. II is true 
4. I, II are true 
 
Subtopic:  Bohr's Model of Atom |
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Given below are two statements: 
Assertion (A): When light consisting of wavelengths corresponding to the Balmer series is incident on a gas containing \(He^{+}\) ions in the first three excited states - it can be absorbed by the \(He^{+}\) ions.
Reason (R): All the energy levels of the He+ ions are the same as those of the \(H\) atoms.
 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is the correct explanation of (A).
4. Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic:  Spectral Series |
 61%
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Select the correct option based on the statements given below:
Assertion (A): The magnetic moment of a hydrogen-like atom is higher when it is in a state of higher quantum number \(n.\)
Reason (R): The magnetic moment of hydrogen-like atom, as calculated from Bohr's theory, is directly proportional to the principal quantum number \(n.\)
 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is the correct explanation of (A).
4. Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic:  Bohr's Model of Atom |
 76%
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Given below are two statements: 
Assertion (A): The positively charged nucleus of an atom has a radius of almost \(10^{-15}~\text{m}\).
Reason (R): I\(\alpha\)-particle scattering experiment, the distance of the closest approach for \(\alpha\)-particle is \(\approx 10^{-15}~m\).
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Various Atomic Models |
 59%
From NCERT
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R): 
 
Assertion (A): The hydrogen atom consists of only one electron but its emission spectrum has many lines.
Reason (R): Only Lyman series is found in the absorption spectrum of hydrogen atoms whereas in the emission spectrum, all the series are found.

In the light of the above statements choose the correct answer from the options given below:
 
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false.


 
Subtopic:  Spectral Series |
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