Atoms
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Time : 30 Minute
- 1.The energy equivalent to one atomic mass unit is:
- A.
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- B.
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- C.
9.23 Mev
- D.
931 MeV
- 2.The ratio of radii of orbits corresponding to first and second excited states of hydrogen atom is:
- A.
1 : 3
- B.
1 : 2
- C.
2: 3
- D.
4 : 9
- 3.The series of hydrogen spectrum which lies in visible region is:
- A.
Lymann series
- B.
Balmer series
- C.
Paschen series
- D.
None of the above
- 4.The order of velocity of electron in ground sate of hydrogen is:
- A.
10 m/s
- B.
106 m/s
- C.
10-6 m/s
- D.
108 m/s
- 5.The diameter of the first orbit of the hydrogen atom is of the order of:
- A.
0.5 Ǻ
- B.
1 Ǻ
- C.
2 Ǻ
- D.
4 Ǻ
- 6.The simple Bohr model cannot be directly applied to calculate the energy levels of an atom with many electrons. This is because:
- A.
Of the electrons not being subject to a central force
- B.
Of the electrons colliding with each other
- C.
Of screening effect
- D.
The force between the nucleus and an electron will no longer be given by Coulomb’s Law
- 7.Two H atoms in the ground state collide inelastically. The maximum amount by which their combined kinetic energy is reduced is:
- A.
10.20 eV
- B.
20.40 eV
- C.
13.6 eV
- D.
27.2 eV
- 8.Hydrogen atom is excited from ground sate to another state with principal quantum number equal to 4. Then the number of spectral lines in the emission spectra will be:
- A.
2
- B.
3
- C.
5
- D.
6
- 9.Taking the Bohr radius as ao = 53pm, the radius of Li2+ ion in its ground state, on the basis of Bohr’s model, will be about:
- A.
53 pm
- B.
27 pm
- C.
18 pm
- D.
13 pm
- 10.Which of the following transitions in a hydrogen atom emit a photon of highest frequency?
- A.
N = 2 to n = 6
- B.
N = 6 to n = 2
- C.
N = 1 to n = 2
- D.
N = 2 to n = 1
- 11.In a Rutherford scattering experiment, when a projectile of charge Q and mass M approaches a target nucleus of charge q and mass m, the distance of closest approach is r. The energy of the projectile is:
- A.
Directly proportional to mass M
- B.
Directly proportional to
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- C.
Directly proportional to Qq
- D.
Directly proportional to Q
- 12.The positron was discovered by:
- A.
Chadwick
- B.
Bohr
- C.
Maxwell
- D.
Anderson
- 13.Energy of electron in t6hye 1st orbit of H-atom is:
- A.
–13.6 MeV
- B.
–13.6 eV
- C.
–13.6 J
- D.
13.6 J
- 14.With increasing quantum number, the energy difference between adjacent energy levels in atoms:
- A.
Increases
- B.
Decreases
- C.
Remains constant
- D.
First increases then decreases
- 15.
![. Let there be a system of energy levels of a certain atom. When the system moves from 2E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from level to E is: - ProProfs]( ". Let there be a system of energy levels of a certain atom. When the system moves from 2E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from level to E is:")
. Let there be a system of energy levels of a certain atom. When the system moves from 2E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from level to E is:- A.
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- B.
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- C.
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- D.
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