If the electron in a hydrogen atom jumps from an orbit with level n2 = 3 to an orbit with level n1 = 2, the emitted radiation has a wavelength given by
λ = 6/R
λ = R/6
The Bohr model of atoms
Assumes that the angular momentum of electrons is quantized
Uses Einstein’s photoelectric equationÂ
Predict continuous emission spectra for atoms
Predicts the same emission spectra for all types of atoms
The ground state energy of H-atom is 13.6 eV. The energy needed to ionize H –atom from its second excited state is
1.51 eV
3.4 eV
13.6 eV
12.1 eV
The energy required to excite hydrogen atom from n = 1 to n = 2 state is 10.2 eV. What is the wavelength emitted when it returns to ground state?
1020 × 10-10 m
1220 × 10-10 m
1320 × 10-10 m
920 × 10-10 m
Hydrogen atom emits blue light when it changes from n = 4 energy level to n = 2 level. Which colour of light would the atom emit when it changes from n = 5 level to n = 2 level?
Red
Yellow
Violet
Green
The ionization energy of hydrogen atom is 13.6 eV. Following Bohr’s theory, the energy corresponding to a transition between 3rd and 4th orbit is
3.40 eV
0.85 eV
0.66 eV
An α-particle of energy 5 MeV is scattered through 180o by a fixed uranium nucleus. The distance of the closest approach is of the order of
1 Å
10-10 cm
10-12 cm
10-15 cm
The manifestation of band structure in solids is due to
Heisenberg’s uncertainty principle
Pauli’s exclusion principle
Bohr’s correspondence principle
Boltzmann’s law
When hydrogen atom is in its first excited level, its radius is
Four times, its ground sate radius
Twice, its ground state radius
Same as its ground state radius
Half of its ground state radius
If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n = 2 is
102 eV
Zero
-3.4 eV
6.8 eV