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Q. No.The shortest wavelength of the Paschen series for H-atom is:
1.
\(\dfrac{9}{R}\)
2.
\(\dfrac{16}{R}\)
3.
\(\dfrac{144}{7 R}\)
4.
\(\dfrac{7 R}{144}\)
Subtopic: Hydrogen Spectra |
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Level 2: 60%+
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Identify the correct relationship between potential energy and total energy of an electron in Bohr's model for single electron species.
1. \(\mathrm{PE}=2 \mathrm{TE}\)
2. \(PE=-2TE~\)
3. \(PE=TE\)
4. \(PE=-TE\)
1. \(\mathrm{PE}=2 \mathrm{TE}\)
2. \(PE=-2TE~\)
3. \(PE=TE\)
4. \(PE=-TE\)
Subtopic: Bohr's Theory |
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Level 1: 80%+
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Calculate the velocity of the electron in the first orbit of H-atom.
(me= \(9.1\times10^{-31}\text{kg}\))
1. \(2.18 \times 10^5 \mathrm{~m} / \mathrm{s}\)
2. \(2.18 \times 10^6 \mathrm{~m} / \mathrm{s}\)
3. \(2.18 \times 10^7 \mathrm{~m} / \mathrm{s}\)
4. \(2.18 \times 10^4 \mathrm{~m} / \mathrm{s}\)
(me= \(9.1\times10^{-31}\text{kg}\))
1. \(2.18 \times 10^5 \mathrm{~m} / \mathrm{s}\)
2. \(2.18 \times 10^6 \mathrm{~m} / \mathrm{s}\)
3. \(2.18 \times 10^7 \mathrm{~m} / \mathrm{s}\)
4. \(2.18 \times 10^4 \mathrm{~m} / \mathrm{s}\)
Subtopic: Hydrogen Spectra |
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The ratio of the shortest wavelengths in the Lyman and Balmer series of the H-atom is:
| 1. | \(\dfrac{1}{4}\) | 2. | \(\dfrac{4}{1}\) |
| 3. | \(\dfrac{1}{2}\) | 4. | \(\dfrac{2}{1}\) |
Subtopic: Type of Spectra |
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Find out wavelength of a photon having frequency equal to \(900 ~\text {sec}^{-1}\)
1. \(3.33 \times 10^5 \mathrm{~m} \)
2. \(3.33 \times 10^5 \mathrm{~cm} \)
3. \(3.33 \times 10^7 \mathrm{~m} \)
4. \(3.33 \times 10^4 \mathrm{~m}\)
1. \(3.33 \times 10^5 \mathrm{~m} \)
2. \(3.33 \times 10^5 \mathrm{~cm} \)
3. \(3.33 \times 10^7 \mathrm{~m} \)
4. \(3.33 \times 10^4 \mathrm{~m}\)
Subtopic: Electromagnetic Radiation |
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The de Broglie wavelength of an electron in the 4th orbit is:
(where, \( a_0\) = radius of 1st orbit )
1. \(2 \pi a_0\)
2. \(8 \pi a_0\)
3. \(6 \pi a_0\)
4. \(4 \pi a_0\)
Subtopic: De Broglie Equation |
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Consider the following statements:
| Statement I: | The number of emitted photoelectrons increases with increase in the frequency of incident light. |
| Statement II: | The kinetic energy of emitted photoelectrons increases with increase in the frequency of incident light. |
| 1. | Statement I is true but Statement II is false. |
| 2. | Statement I is false but Statement II is true. |
| 3. | Both Statement I and Statement II are true. |
| 4. | Both Statement I and Statement II are false. |
Subtopic: Photo Electric Effect |
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The angular momentum of an electron in an orbit of radius \(\mathrm{R}\) in a hydrogen atom is directly proportional to ____.
| 1. | \(\mathrm{R}\) | 2. | \(\dfrac{1}{R}\) |
| 3. | \(\dfrac{1}{\sqrt{R}}\) | 4. | \(\sqrt{R}\) |
Subtopic: Bohr's Theory |
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Subtopic: Number of Electron, Proton & Neutron |
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For an atom, what is the maximum number of electrons that can have the following quantum numbers: \(\mathrm{(i) \mathrm{n}=4 (ii) m_l= +1, (iii) \mathrm{m}_{\mathrm{s}}=-\frac{1}{2} ?}\)
1. Two
2. Four
3. One
4. Three
1. Two
2. Four
3. One
4. Three
Subtopic: Number of Electron, Proton & Neutron |
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