A dye absorbs a photon of wavelength and re-emits the same energy into two photons of wavelengths and respectively. The wavelength is related to and as-
1.
2.
3.
4.
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The energy of an electron in the first Bohr's orbit of an H-atom is -13.6 eV. The possible energy value (s) of the excited state(s) for electrons in Bohr's orbits of hydrogen is (are):
1. -3.4 eV
2. -4.2 eV
3. -6.8 eV
4. +6.8 eV
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Assertion (A): | The angular momentum of an electron in an atom is quantized. |
Reason (R): | In an atom, only those orbits are permitted in which the angular momentum of the electron is a natural number multiple of h/2π. |
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. | (A) is false but (R) is true. |
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For any H-like system, the ratio of velocities of I, II & III orbit i.e., will be:
1. 1 : 2 : 3
2. 1 : 1/2 : 1/3
3. 3 : 2 : 1
4. 1 : 1 : 1
The concept that contradicts the Bohr Model of an atom is:
1. | Rutherford Model | 2. | Heisenberg's Uncertainty Principle |
3. | J.J. Thomson Model | 4. | Photoelectric Effect |
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An ion among the following that has the same radius as a hydrogen atom, having n=1, is
1.
2.
3.
4.
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Assertion (A): | Bohr’s orbits are also called stationary states. |
Reason (R): | Electrons are stationary in an orbit. |
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. | (A) is false but (R) is true. |
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Assertion (A): | The radius of the second orbit of He+ is equal to that of the first orbit of hydrogen. |
Reason (R): | The radius of an orbit in hydrogen-like species is directly proportional to n and inversely proportional to Z. |
1. | Both (A) and (R) are True and (R) is the correct explanation of the (A). |
2. | Both (A) and (R) are True and (R) is not the correct explanation of the (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
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If the size of the first orbit of the hydrogen atom is 5.29 nm, the size of the second orbit of He+ is
1. 2.65 nm
2. 21.16 nm
3. 10.58 nm
4. 5.29 nm
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The wavelength of a certain line in the Balmer series is observed to be 4341 Ao for hydrogen atoms.
The electronic transition among the following may be:
1. 3 → 2
2. 4 → 1
3. 5 → 2
4. 5 → 3
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