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
An ion among the following that has the same radius as a hydrogen atom, having n=1, is
1.
2.
3.
4.
The number of electrons with the azimuthal quantum number l = 1 and 2 for Cr 24 in ground state is
1. 16 and 5
2. 12 and 5
3. 16 and 4
4. 12 and 4
The wavelength of the radiation emitted when in a H atom, the electron falls from infinity to stationary state (n=1), is:
1.
2. 192 nm
3. 406 nm
4. 91 nm
The number of protons, neutrons and electrons in \( _{71}^{175}Lu\) respectively, are:
1. 104, 71 and 71
2. 71, 71 and 104
3. 175, 104 and 71
4. 71, 104 and 71
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 |
Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. The work function (W0) of the metal is:
1. 3.109 × 10–20 J
2. 2.922 × 10–19 J
3. 4.031 × 1019 J
4. 2.319 × 10–18 J
Determine the maximum number of emission lines produced when an electron in a hydrogen atom transitions from the n = 6 energy level to the ground state :
1. 30
2. 21
3. 15
4. 28
The ionization energy for H atom in the ground state is \(2.18 \times10^{-18}~ \mathrm J.\) The process energy requirements will be: \(( He^+(g) \rightarrow He^{2+}(g) + e^- )\)
1. | \(8.72 \times10^{-18}~\mathrm J\) | 2. | \(7.54 \times10^{-18}~\mathrm J\) |
3. | \(5.67 \times10^{-17}~\mathrm J\) | 4. | \(2.18 \times10^{-17}~\mathrm J\) |
The ejection of the photoelectron from the silver metal can be stopped by applying a voltage of 0.35 eV when the radiation having a wavelength of 256.7 nm is used. The work function for silver metal is:
1. 3.40 eV
2. 5.18 eV
3. 4.48 eV
4. –4.40 eV