Atoms  MCQs

MCQs of Atoms

Showing 41 to 50 out of 146 Questions
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41.
The fine structure of hydrogen spectrum can be explained by _____
(a) the presence of neutrons in the nucleus
(b) the finite size of nucleus
(c) the orbital angular momentum of electrons
(d) the spin angular momentum of electrons
Answer:

Option (d)

42.
When a moving elementary particle with kinetic energy 11.5 eV strikes head on with a free stationary H-atom, then _____
(a) if the particle an electron, the H-may get excited
(b) the H-atom may move with kinetic energy 11.5 eV irrespective of the nature of elementary particle
(c) if the particle is a neutron, the H-atom may get excited
(d) if the particle is a neutron, H-atom must get excited
Answer:

Option (a)

43.
Photon of energy 13.4 eV is incident on hydrogen atom in the ground state. The electron of the atom will be in the energy state _____
(a) 3
(b) 2
(c) 1
(d) 4
Answer:

Option (c)

44.
Find the kinetic energy of hydrogen atom in the ground state if potential energy is taken as zero at ground state ?
(a) zero
(b) 27.2 eV
(c) 13.6 eV
(d) 54.4 eV
Answer:

Option (c)

45.
A particular hydrogen like atom has its ground state binding energy 122.4 eV. It is in its ground state. Then _____
(a) its atomic number is 4
(b) an electron of 90 eV can excite it
(c) an electron of kinetic energy nearly 91.8 eV can be brought to almost rest by this atom
(d) an electron of kinetic energy 2.6 eV may emerge from the atom when electron of kinetic energy 126 eV collides with this atom
Answer:

Option (c)

46.
The wavelength of the spectral line that corresponds to a transition in hydrogen atom from n = 10 to ground state would be _____ .[In which part of electro-magnetic spectra does this line lie ?]
(a) 92.25 nm, ultraviolet
(b) 92.25, infrared
(c) 86.95 nm, ultraviolet
(d) 97.25 nm, ultraviolet
Answer:

Option (a)

47.
Binding energy of an electron in the ground state of He is equal to 24.6 eV. The energy required to remove both the electrons is _____
(a) 24.6 eV
(b) 49.2 eV
(c) 79 eV
(d) 38.2 eV
Answer:

Option (c)

48.
Difference between n th and (n + 1) th Bohr's radius of hydrogen atom is equal to (n - 1) th Bohr's radius. The value of n is _____
(a) 1
(b) 2
(c) 3
(d) 4
Answer:

Option (d)

49.
If the elements with principal quantum number n > 3 do not exist in nature, the number of possible elements will be _____
(a) 28
(b) 60
(c) 14
(d) 105
Answer:

Option (a)

50.
In which of the following transitions of an electron in hydrogen atom the energy variation is minimum ?
(a) From n =5 to n = 4
(b) From n =3 to n = 2
(c) From n =2 to n = 1
(d) From n =4 to n = 3
Answer:

Option (a)

Showing 41 to 50 out of 146 Questions
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