Which of the following transitions in a hydrogen atom emits off the highest frequency?
n = 1 to n = 2
n = 2 to n = 6
n = 2 to n = 1
n = 6 to n = 2
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 valence electron in alkali metal is a
ƒ - electron
p -electron
s -electron
d -electron
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
The spectrum obtained from a sodium vapour lamp is an example of
Band spectrum
Continuous spectrum
Emission spectrum
Absorption spectrum
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
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
When electron jumps from n = 4 to n = 2 orbit, we get
Second line of Lyman series
Second line of Balmer series
Second line of Paschen series
An absorption line of Balmer series
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
1.51 eV
0.85 eV
0.66 eV
The Bohr model of atoms
Assumes that the angular momentum of electrons is quantized
Uses Einstein’s photoelectric equation
Predict continuous emission spectra for atoms
Predicts the same emission spectra for all types of atoms
