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Chapter 20
ATOMIC SPECTRA
Encircle the most appropriate answer among the following option
1. Rutherford concluded that central part of an atom is choose which one is correct:
(a) Electrically neutral
(b) Positively charged
(c) Negatively charged
(d) None of above
2. The first theory about the structure of an atom was introduced by.
(a) Neil Bohr
(b) Einstein
(c) Compton
(d) Rutherford
3. Bohr’s postulates explained by choose which one is correct:
(a) de-Broglie
(b) Einstein
(c) Newton
(d) none
4. Operation of a laser depends upon choose which one is correct:
(a) The existence of atoms in metastable state
(b) The existence of atoms in ground state
(c) The existence of atoms in excited state
(d) None of these
5. Study of hydrogen visible spectrum in choose which one is correct:
(a) 1886
(b) 1887
(c) 1895
(d) 1885
6. Bohr was presented atomic model of hydrogen in choose which one is correct:
(a) 1913
(b) 1919
(c) 1918
(d) 1905
7. The process by which lesser beam can be used to generate 3- dimensional images of objects is called choose which one is correct:
(a) Holography
(b) Geo graphy
(c) Tomography
(d) Radio graphy
8. The scientist who studies the spectrum of hydrogen in visible light, wavelength range was choose which one is correct:
(a) Rydberg
(b) Bohr
(c) Balmer
(d) Paschen
9. The first series, which was identified in the spectrum of hydrogen is called choose which one is correct:
(a) Balmer series
(b) Lyman series
(c) Paschen series
(d) Brakett series
10. Balmer series was identified in choose which one is correct:
(a) 1685
(b) 1785
(c) 1985
(d) 1885
11. Balmer series lies in that region of electromagnetic wave spectrum, which is known as choose which one is correct:
(a) Visible region
(b) Invisible region
(c) Ultraviolet region
(d) Infra-red region
12. The results of spectra obtained by Balmer were expressed in 1896 by choose which one is correct:
(a) Newton
(b) Bohr
(c) Rydberg
(d) Planck
13. The process of formation of spectrum is known as choose which one is correct:
(a) Diffraction
(b) Interferences
(c) Refraction
(d) Spectroscopy
14. The value of Rydberg constant is choose which one is correct:
(a) 1.0974 x 107 m-1
(b) 1.0974 x 10-7 m-1
(c) 1.0974 x 106 m-1
(d) 1.0974 x 10-6 m-1
15. Spectrum shows the number of component colour present in certain light in terms of choose which one is correct:
(a) Frequency
(b) Energy
(c) Wavelength
(d) All of the above
16. Tick the series lies in visible region choose which one is correct:
(a) Paschen series
(b) Lyman series
(c) Pfund series
(d) Balmer series
17. Tick the series lies infrared region choose which one is correct:
(a) Paschen series
(b) Brakett series
(c) Pfund series
(d) All of the above
18. In the production of laser beam for each incident photon, we will have two photons going choose which one is correct:
(a) In the same direction
(b) In opposite direction
(c) At right angle to each other
(d) In arbitrary direction
19. During the transition of electron of hydrogen atom from higher orbit to a third orbit, a photon of choose which one is correct:
(a) Paschen series is emitted
(c) Lyman series is emitted
(b) Balmer series is emitted
(d) Brakett series is emitted
20. In the general formula for spectral series, if we put P = 3, we get the formula for choose which one is correct:
(a) Paschen series
(b) Blamer series
(c) Lyman series
(d) Brakett series
21. An electron of the hydrogen atom in the second orbit, is called its choose which one is correct:
(a) Ground state
(b) Ionized state
(c) Excited state
(d) None of these
22. Which of the following is one of the spectral series of atomic hydrogen choose which one is correct:
(a) Brockett series
(b) Balmer series
(c) P fund series
(d) All of above
23. An example of an absorption spectrum is the spectrum of choose which one is correct:
(a) Sodium vapour
(b) Molten iron
(c) Atomic hydrogen
(d) Mercury vapour lamp
24. The radiations emitted from hydrogen filled discharge tube shows which among the following choose which one is correct:
(a) Continuous spectrum
(b) Line spectrum
(c) Band spectrum
(d) None of these
25. The spectral series that contains transitions terminating on the ground level of hydrogen is called choose which one is correct:
(a) Paschen series
(b) P fund series
(c) Balmer series
(d) Lyman series
26. In hydrogen spectrum, which one the following series lies in the ultraviolet region choose which one is correct:
(a) Lyman series
(b) Balmer series
(c) P fund series
(d) Brackett series
27. In hydrogen atom, which one of the following series lies in the infrared region choose which one is correct:
(a) Lyman series
(b) Brackett series
(c) Paschen series
(d) Balmer series
28. The longest wavelength of light which ionizes a hydrogen atom is choose which one is correct:
(a) 912 AO
(b) 0.74 AO
(C) 400 AO
(d) 720 AO
29. Radiations with wavelengths longer than red light is called choose which one is correct:
(a) Visible radiation
(b) Infrared radiation
(c) Ultraviolet radiation
(d) X-rays
30. Radiation, with wavelength shorter than violet is called choose which one is correct:
(a) Ultraviolet radiation
(b) Infrared radiation
(c) Visible radiation
(d) None of these
31. Electromagnetic rays which lies above the x-rays region are called choose which one is correct:
(a) y-rays
(b) Infrared radiations
(c) Ultraviolet radiation
(d) None of these
32. Rutherford’s nuclear model predicted choose which one is correct:
(a) Discrete spectra of atoms
(b) Continuous spectra of atoms
(c) Both (a) and (b)
(d) None of these
33. For the stability of nuclear model, Rutherford proposed choose which one is correct:
(a) Static equilibrium
(b) Dynamic equilibrium
(c) Neutral equilibrium
(d) None of these
34. According to Rutherford nuclear model, the major constituents of the nucleus are choose which one is correct:
(a) Neutrons and electrons
(b) Protons and positrons
(c) Neutron and protons
(d) Protons and electrons
35. Net force on an electron in an orbit around the nucleus will be choose which one is correct:
(a) Positive
(b) Zero
(c) Negative
(d) None of these
36. In Bohr atomic model, the electron does not fall into the nucleus because choose which one is correct:
(a) The electron is not a particle
(b) The quantum rules does not allow it
(c) The electrostatic attraction is balanced by mechanical force
(d) None of these
37. Brackett series is obtained when electronic transitions terminate on the choose which one is correct:
(a) 1st orbit
(b) 2nd orbit
(c) 3 rd orbit
(d) 4th orbit
38. In Bohr’s atomic model, the lowest orbit corresponds to choose which one is correct:
(a) Zero energy
(b) The minimum energy
(c) The maximum energy
(d) None of these
39. Most commonly used type of gas laser is choose which one is correct:
(a) Helium-Neon
(b) Carbon dioxide
(c) Argon ion
(d) All of above
40. mvr is the expression for choose which one is correct:
(a) Linear momentum
(b) Angular momentum
(c) Torque
(d) None of these
41. The velocity of laser light is choose which one is correct:
(a) Less than ordinary light
(b) More than ordinary light
(c) Equal to ordinary light
(d) None of these
42. The radii of different orbits around the nucleus of an atom is given by choose which one is correct:
(a) r2n = nr1
(b) rn = n r21
(c) rn =n2r1
(d) rn nr1
43. Balmer series is obtained when all the transitions of electron terminate on choose which one is correct:
(a) 4th orbit
(b) 2nd orbit
(c) 5th orbit
(d) 3rd orbit
44. Reflecting mirrors in laser is used to choose which one is correct:
(a) Further stimulation
(b) For producing more energetic lasers
(c) Both (a) and (b)
(d) None of these
45. The numerical value of ground state energy of an electron in an orbit is the measure of choose which one is correct:
(a) Excitation energy
(b) Excitation potential
(c) Ionization energy
(d) None of these
46. In He-Ne laser, the laser action is produced by choose which one is correct:
(a) Ne only
(b) He-Ne both
(c) Electrons of He
(d) Electrons of Ne
47. If the ionization energy of hydrogen atom is 13.6 eV, its ionization potential will be choose which one is correct:
(a) 136.0 volt
(b) 3.0 volt
(c) 13.6 volt
(d) None of these
48. The SI unit of Rydberg constant is choose which one is correct:
(a) ms-1
(b) m
(c) sm-1
(d) m-1
49. The experimental value of Rydberg’s constant is choose which one is correct:
(a) 1.0974 x 107m-1
(b) 1.0974 x 10-7m-1
(c) 10.97 x 10-7m-1
(d) 109.1 x 10-9 m-1
50. The excited atoms returns to their ground state in choose which one is correct:
(a) 10-10 sec
(b) 10-8sec
(c) 10-6 sec
(d) 10-11 sec
51. The diameter of an atom is of the order of choose which one is correct:
(a) 10 16 m
(b) 10-8 m
(c) 10 -10 m
(d) 10 10 m
52. Life time of metastable states is choose which one is correct:
(a) 10-6 sec or more
(b) I0-3 sec or more
(c) I0--5 sec or more
(d) None of these
53. Laser beam can be used to generate three dimensional images of object in a process called choose which one is correct:
(a) Holography
(b) Tomography
(c) None of these
54. The value of Planck’s constant is choose which one is correct:
(a) 109 Nm2c-2
(b) 6.63 x 10-34 J.s
(c) 9.1 x 10-31 kg
(d) None
55. The radius of 1 st Bohr’s orbit for hydrogen is choose which one is correct:
(a) 0.053 nm
(b) 0.53 nm
(c) 0.53 m
(d) None of these
56. Helium-Neon laser discharge tube contains neon choose which one is correct:
(a) 82%
(b) 15%
(c) 25%
(d) 85%
57. For production of X-rays, the target must be of choose which one is correct:
(a) High melting point
(b) Low melting point
(c) Very hard
(d) none
58. The I Bohr atom in the hydrogen atom has radius choose which one is correct:
(a) 3.56 x 10-10 m
(b) 0.053x 10-11 m
(c) 0.53 x 10-11m
(d) 5.30x 10-11m
59. The idea of laser device was first introduced by C.H. Townes and Authers Schowlan is choose which one is correct:
(a) 1972
(b) 1965
(c) 1958
(d) 1913
60. Laser can be made by creating choose which one is correct:
(a) Population inversion
(b) Metastable state
(c) Assembly
(d) All
61. What is speed of electron in the first Bohr orbit?
(a) 2.19 x 106 m/s
(b) 1.6 x 106
(c) 2.2 x 10-6
(d) 3 x 10-8
62. When an electron exist in its lowest state it is called choose which one is correct:
(a) Ground state
(b) Excited state
(c) Both (a) and (b)
(d) None of these
63. The photons emitted in inner shell transition are called choose which one is correct:
(a) VB-particle
(b) Characteristic x-rays
(c) y-particle
(d) None of these
64. X-rays were discovered by choose which one is correct:
(a) Curie
(b) Henry Becquerel
(c) Rontgen
(d) None of these
65. X-rays are similar in nature to choose which one is correct:
(a) trays
(b) Positive rays
(c) -particle
(d) None of these
66. X-rays are choose which one is correct:
(a) Electromagnetic waves
(b) Mechanical waves
(c) Transverse waves
(d) Longitudinal waves
67. The transition’s of electrons in the hydrogen atom result in the emission of spectral lines in the choose which one is correct:
(a) Visible region
(b) Infra red region
(c) Ultra violet region
(d) Any of these
68. X-ray tube used for production of X-rays contains choose which one is correct:
(a) Air at pressure of 760 mm of Hg
(b) Air at pressure of 76 cm of Hg
(c) No air at all
(d) None of these
69. Kß x-ray is emitted when an electron from choose which one is correct:
(a) M shell fills the vacancy of K shell
(b) L shell fills the vacancy of K shell
(c) K shell fills the vacancy of M shell
(d) Both (a) and (b)
70. The characteristic x-rays appear as choose which one is correct:
(a) Discrete spectrum
(b) Continuous spectrum
(c) Band spectrum
(d) Discrete lines on continuous spectrum
71. Braking radiation causes choose which one is correct:
(a) Discrete spectrum
(b) Continuous spectrum
(c) Band spectrum
(d) Line spectrum
72. By CAT scans, we can detect the density difference of the order of choose which one is correct:
(a) 1%
(b) 15%
(c) 10%
(d) 50%
73. X-rays are diffracted by crystal but not by a diffraction grating because choose which one is correct:
(a) The ions in a crystal are well arranged
(b) The lines in a diffraction grating cannot reflect x-rays
(c) The penetrating power of x-rays is in high in diffraction grating
(d) The wavelength of x-rays are the same order of magnitude as the separation between the atom in the crystal
74. The maximum frequency in the spectrum from x-rays tube is directly proportional to the choose which one is correct:
(a) Number of incident electron
(b) The kinetic energy of the incident electron
(c) The soft target, which can easily emit electrons
(d) None of these
75. The characteristic x-rays spectrum is due to choose which one is correct:
(a) The illumination of target metal by ultraviolet radiation
(b) The bombardment of the target by protons
(c) The bombardment of the target by electrons
(d) None of these
76. The minimum wavelength of x-rays can further be reduced by choose which one is correct:
(a) Reducing the press use or cooling the target
(b) Increasing the temperature of the filament
(c) Using the target element of higher atomic number
(d) Increasing the potential difference
77. The penetrating power of x-rays is comparable with that of choose which one is correct:
(a) ß-rays
(b) -rays
(c) x-rays
(d) None of these
78. The penetrating power of x-rays depends upon their choose which one is correct:
(a) Frequency
(b) Applied voltage
(c) Wavelength
(d) None of these
79. When x-rays are passed through aluminium sheets, what happens to their thickness choose which one is correct:
(a) Decreases
(b) Increases
(c) Remain the same
(d) None of these
80. X-rays are choose which one is correct:
(a) Of unknown nature
(b) High energy photons
(c) High energy electrons
(d) High energy positrons
81. The x-rays diffraction with crystal was first studied by choose which one is correct:
(a) W.H Bragg
(b) W.L Bragg
(c) Michelson
(d) None of these
82. X-ray photons cannot produce pair production because choose which one is correct:
(a) Electromagnetic waves
(b) Rest mass and charge is zero
(c) Energy is less than rest mass energy
(d) None of these
83. K-series of characteristic x-rays spectrum results when all the transitions of inner-shell electrons terminate an choose which one is correct:
(a) K-shell
(b) VI-shell
(c) L-shell
(d) None of these
84. The first spectra line of K-series of characteristics x-rays spectrum results when choose which one is correct:
(a) M-shell electron fall into K-shell
(b) L-shell electron into K-shell
(c) N-shell electron fall into M-shell
(d) None of these
85. Most efficient tube for production of x-rays was designed by choose which one is correct:
(a) Maxwell in 1913
(b) Einstein in 1913
(c) Dr. Coolidge 1913
(d) Dr. Rontgen in 1913
86. For the production of x-rays, the target metal should be bombarded by choose which one is correct:
(a) Electrons
(b) Neutrons
(c) Protons
(d) Positrons
87. Quality of x-rays depends upon choose which one is correct:
(a) Accelerating voltage
(b) Filament current
(c) Material of the target
(d) Both (a) and (c)
88. The velocity of x-rays is equal to that of choose which one is correct:
(a) -rays
(b) -rays
(c) trays
(d) Speed of light
89. X-rays can be used to choose which one is correct:
(a) Detect Bone Fracture
(b) Detect Flows in welding
(c) Control of Cancer
(d) All of above
90. X-rays exhibit the phenomenon of choose which one is correct:
(a) Diffraction
(b) Interference
(c) Polarization
(d) All of the above
91. The rest mass of x-ray photon is choose which one is correct:
(a) Zero
(b) 1.67 x 10-27 kg
(c) 9.1 x 10-31 kg
(d) None
92. The reverse process of photo-electric effect is called choose which one is correct:
(a) Annihilation of matter
(b) Compton effect
(c) Pair production
(d) X-rays
93. The transitions of inner shell electrons in heavy atoms give rise to the emission of choose which one is correct:
(a) High energy photon or x-rays
(b) High energy -rays
(c) Low energy photons or x-rays
(d) High energy ß-rays
94. Laser is device which can produce choose which one is correct:
(a) Coherent beam of light
(b) Monochromatic beam of light
(c) An intense beam of light
(d) All of above
95. The idea of laser was introduced by choose which one is correct:
(a) C.H. Townes and Arthur L Schaw Law
(b) Dr. Grattling
(c) Frank whittle
(d) Dr, C-gilbert young
96. The branch of Physics in which laser is studied choose which one is correct:
(a) Optics
(b) Photonics
(c) Plasma
(d) None
97. The duration of a laser pulse is 10-8 see. The uncertainty in its energy will be choose which one is correct:
(a) 10.500 x 10-26 J
(b) 6.625 x 10-28 J
(c) 6.625 x 10-26 J
(d) 1.050 x 10-28
98. Different types of lasers are choose which one is correct:
(a) Two
(b) Three
(c) Five
(d) None
99. Characteristic x-rays are produced from choose which one is correct:
(a) Heavy element
(b) Light element
(c) Inner shell
(d) Both
100. An atom can reside in excited state for choose which one is correct:
(a) 10-8
(b) One second
(c) 10-10
(d) More than one second