+ 2 Physics * 2014-2015 * Unit – 6 Atomic Physics * Maximum marks : 90 1. At atmospheric pressure, air and other gases are …………… conductors of electricity. a) good b) semi c) poor d) rich 2. Electric current may be passed through a gas by allowing ……………. to pass through them. a) light b) infra-red c) X –rays d) none of the above 3. Electrons were discovered by ……………… a) Millikan b) Goldstein c) Einstein d) Thomson 4. …………………… is an arrangement to study the conduction of electricity through gases. a) X-ray tube b) Coolidge tube c) discharge tube d) GM counter 5. In a discharge tube, the potential difference applied between the two electrodes is ……………… a) 10000 V b) 20000 V c) 60000 V d) 50000 V 6. In a discharge tube, the discharge of electricity through gases starts at a pressure of about ………… a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg 7. In a discharge tube, the positive column is produced at a pressure of about ……………… a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg 8. In a discharge tube, Crooke’s dark space is produced at a pressure of about …………… a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg 9. Cathode rays travel with a velocity up to ………………. of the velocity of light. a) (1 /100) th b) (1 /10) th c) (1 /1000) th d) (1 /10000) th 10. Canal rays were discovered by ……………….in the year 1886. a) Millikan b) Goldstein c) Einstein d) Thomson 11. In 1887, ………………… measured the specific charge of the cathode ray particles. a) Millikan b) Goldstein c) Einstein d) Thomson 12. If V is the potential difference between the two plates and d is the distance between them, then E = … a) V d b) d / V c) V / d d) V 2 / d 13. e / m value of the electron is ………………….. a) 1.7592 X 10 11 C kg -1 b) 1.7592 X 10 11 C kg c) 1.602 X 10 19 C kg -1 d) 1.602 X 10 -19 C kg -1 14. Millikan’s experiment is used for the measurement of ………… of the electron. a) density b) specific charge c) mass d) charge 15. In Millikan’s experiment, the potential difference applied between the two electrodes is ……… a) 10000 V b) 20000 V c) 60000 V d) 50000 V 16. The net downward force acting on the oil drop = …………….. a) zero b) maximum c) minimum d) ⅓ X 4 π a3 ( ρ - ζ ) g 17. In Millikan’s experiment, the charge of the electron q = …………… a) ne b) n 2 e c) n 3 e d) e / n 18. In Millikan’s experiment, the charge value of the electron = …………………. a) 1.7592 X 10 11 C b) 1.7592 X 10 11 C c) 1.602 X 10 19 C d) 1.602 X 10 -19 C 19. The concept of atoms was proposed by ……………… a) Bohr b) Thomson c) Dalton d) Prout 20. Prout suggested that all elements are made up of atoms of ………………… a) carbon b) helium c) hydrogen d) nitrogen 21. Atom is a sphere of positive charge in which the electrons are embedded. This was suggested by ..… a) Bohr b) Thomson c) Dalton d) Prout 22. In the case of hydrogen atom, Thomson’s model gives only one spectral line of about …………… a) 3300 A o b) 2300 A o c) 1300 A o d) 4300 A o 23. The scattering of α particles provide useful information about the structure of the ……………….. a) atom b) hydrogen c) CO 2 d) oxygen …………… Continued in Page - 2
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
+ 2 Physics * 2014-2015 * Unit – 6 Atomic Physics * Maximum marks : 90
1. At atmospheric pressure, air and other gases are …………… conductors of electricity.
a) good b) semi c) poor d) rich
2. Electric current may be passed through a gas by allowing ……………. to pass through them.
a) light b) infra-red c) X –rays d) none of the above
3. Electrons were discovered by ………………
a) Millikan b) Goldstein c) Einstein d) Thomson
4. …………………… is an arrangement to study the conduction of electricity through gases.
a) X-ray tube b) Coolidge tube c) discharge tube d) GM counter
5. In a discharge tube, the potential difference applied between the two electrodes is ………………
a) 10000 V b) 20000 V c) 60000 V d) 50000 V
6. In a discharge tube, the discharge of electricity through gases starts at a pressure of about …………
a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg
7. In a discharge tube, the positive column is produced at a pressure of about ………………
a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg
8. In a discharge tube, Crooke’s dark space is produced at a pressure of about ……………
a) 100 mm of Hg b) 1 mm of Hg c) 10 mm of Hg d) 0.01 mm of Hg
9. Cathode rays travel with a velocity up to ………………. of the velocity of light.
a) (1 /100)th
b) (1 /10)th
c) (1 /1000)th
d) (1 /10000)th
10. Canal rays were discovered by ……………….in the year 1886.
a) Millikan b) Goldstein c) Einstein d) Thomson
11. In 1887, ………………… measured the specific charge of the cathode ray particles.
a) Millikan b) Goldstein c) Einstein d) Thomson
12. If V is the potential difference between the two plates and d is the distance between them, then E = …
a) V d b) d / V c) V / d d) V2 / d
13. e / m value of the electron is …………………..
a) 1.7592 X 1011
C kg-1
b) 1.7592 X 1011
C kg c) 1.602 X 10
19 C kg
-1 d) 1.602 X 10
-19 C kg
-1
14. Millikan’s experiment is used for the measurement of ………… of the electron.
a) density b) specific charge c) mass d) charge
15. In Millikan’s experiment, the potential difference applied between the two electrodes is ………
a) 10000 V b) 20000 V c) 60000 V d) 50000 V
16. The net downward force acting on the oil drop = ……………..
a) zero b) maximum c) minimum d) ⅓ X 4 π a3 ( ρ - ζ ) g
17. In Millikan’s experiment, the charge of the electron q = ……………
a) ne b) n2
e c) n3
e d) e / n
18. In Millikan’s experiment, the charge value of the electron = ………………….
a) 1.7592 X 1011
C b) 1.7592 X 1011
C
c) 1.602 X 1019
C d) 1.602 X 10-19
C
19. The concept of atoms was proposed by ………………
a) Bohr b) Thomson c) Dalton d) Prout
20. Prout suggested that all elements are made up of atoms of …………………
a) carbon b) helium c) hydrogen d) nitrogen
21. Atom is a sphere of positive charge in which the electrons are embedded. This was suggested by ..…
a) Bohr b) Thomson c) Dalton d) Prout
22. In the case of hydrogen atom, Thomson’s model gives only one spectral line of about ……………
a) 3300 Ao
b) 2300 Ao c) 1300 A
o d) 4300 A
o
23. The scattering of α particles provide useful information about the structure of the ………………..
a) atom b) hydrogen c) CO 2 d) oxygen
…………… Continued in Page - 2
Page - 2
24. The diameter of the atom is about …………..
a) 10-20
m b) 10-10
m c) 10-14
m d) 1010
m
25. The diameter of the nucleus is about …………….
a) 10-20
m b) 10-10
m c) 10-14
m d) 1010
m
26. According to electromagnetic theory, an accelerated electric charge must radiate energy in the form of ……
a) light b) infra-red rays c) X –rays d) electromagnetic waves
27. An electron revolving in the stationary orbit does not radiate ………...
a) lepton b) energy c) meson d) particle
28. According to Bohr’s quantization condition, the angular momentum of the electron = ……………
a) h / 2 b) 2 π / n h c) nh / 2π d) 2π nh
29. The radius of the nth
orbit of the electron is proportional to the square of the ……… quantum number
a) spin b) principal c) magnetic d) angular momentum
30. Bohr radius value r1 = …………………
a) 0.63 Ao b) 0.83 A
o c) 0.53 A
o d) 0.43 A
o
31. The energy of the electron En = ……………..
a) - z2me
4 / 8ε0
2n
2h
2 b) z
2me
4 / 8ε0
2n
2h
2 c) n
2h
2ε0 / π mze
2 d) - z
2me
4 / 4ε0
2n
2h
2
32. 1 electron volt = ……………… J
a) 1.602 X 1019
b) 1.602 X 10-19
c) 9.11 X 10-31
d) 9.11 X 10 31
33. Rydberg’s constant value R = ……………….
a) 1.094 X 107
m-1
b) 1.602 X 109 c) 1.602 X 10
-19 d) 9.11 X 10
-31
34. The spectral lines of Lyman series of hydrogen atom lie in the ………… region.
a) UV b) Visible c) infra - red d) gamma
35. The spectral lines of Balmer series of hydrogen atom lie in the ……………..
a) UV b) Visible c) infra - red d) gamma
36. The spectral lines of Paschen series of hydrogen atom lie in the ……………….
a) UV b) Visible c) infra - red d) gamma
37. The spectral lines of Brakett series of hydrogen atom lie in the ………………
a) UV b) Visible c) infra - red d) gamma
38. The spectral lines of Pfund series of hydrogen atom lie in the …………..
a) UV b) Visible c) infra - red d) gamma
39. The wavelengths of D1 and D2 lines of sodium are .................
a) 5809Ao ,5896 A
o b) 5986A
o ,5980 A
o c) 5689A
o ,5690 A
o d) 5896A
o ,5890 A
o
40. The energy required to raise an atom from its normal state into an excited state is called ……. energy.
a) excitation potential b) potential c) kinetic d) stellar
41. The value of ionization potential energy for hydrogen atom is …………
a) 13.6 eV b) 30.6 eV c) 3.4 eV d) 10.2 eV
42. The fine structure of spectral lines can not be explained by ………… theory.
a) Raman b) Newton c) Bohr d) Huygens
43. It is found that when magnetic field is applied to the atom, each of the spectral line is split into
several lines. This effect is called ……… effect.
a) Stark b) Zeeman c) Raman d) Tyndal
44. According to Sommerfeld’s atom model, for any principal quantum number n, there are n possible
sub-shells, out of which one is circular and the remaining are ……………. in shape.
a) elliptical c) semi-circular c) square d) rectangle
45. X-rays were discovered by ……………
a) Raman b) Newton c) Roentgen d) Huygens
46. X-rays are electromagnetic waves of short wavelength in the range of ……………
a) 0.5 Ao to 10 A
o b) 0.5 A
o to 100 A
o c) 0.5 A
o to 1000 A
o d) 10 A
o to 100 A
o
………… Continued in Page - 3
Page – 3
47. Roentgen was awarded Nobel prize in 1901 for the discovery of …………….
a) gamma b) UV c) beta d) X-rays
48. When fast moving electrons are suddenly stopped by a metallic target, ……… are produced.
a) gamma rays b) UV rays c) X-rays d) beta rays
49. In Coolidge tube, a high potential of about …………… is applied between filament F and the target T.
a) 10000 V b) 20000 V c) 60000 V d) 50000 V
50. X-rays are of ……………. types.
a) 3 b) 4 c) 2 d) 5
51. X-rays having wavelength of 4Ao or above are called ………………
a) hard X –rays b) soft X – rays c) medium X – rays d) gamma rays
52. X-rays having low wavelength in the order of 1Ao are called ……………
a) hard X –rays b) soft X – rays c) medium X – rays d) gamma rays
53. The penetrating power of hard X-rays is …………….
a) low b) very low c) high d) zero
54. When X-rays fall on certain metals, they liberate …………………
a) protons b) photons c) electrons d) mesons
55. To detect and measure the intensity of the X-rays, ………………. chamber is used.
a) Thomson b) Bohr c) ionization d) Dalton
56. Any plane containing an arrangement of atoms is known as a …………… plane.
a) lattice b) crystal c) metal d) molecular
57. Laue experiment is used to produce diffraction in ………………...
a) gamma b) UV c) beta d) X-rays
58. Bragg’s law is ……………….
a) 2d tanθ = λ b) d Sinθ = n λ c) 2d Sin θ = n λ d) 2d Cos θ = n λ
59. Bragg’s spectrometer is used to measure the wavelength of ……………
a) gamma b) UV c) beta d) X-rays
60. The minimum wavelength of the radiation emitted in continuous X-ray spectra λ min = ………
a) 12400Ao / V b) 1240 A
o / V c) 124 A
o / V d) 124000A
o / V
61. When an electron jumps from M shell to the K shell, it gives ………in the case of characteristic X-rays.
a) Lβ line b) K β line c) Kα line d) Mβ line
62. The frequency of the spectral line in the characteristic X-rays is directly proportional to the square of the
atomic number of the element. This is called ………………….
a) Moseley’s law b) Stokes’s law c) Newton’s law d) Planck’s law
63. …………. has led to the discovery of new elements like technetium, hafnium etc.
a) Planck’s law b) Stokes’s law c) Newton’s law d) Moseley’s law
64. In normal population, the number atoms in the ground state is ………… than the excited state.
a) smaller b) lesser c) greater d) lower
65. In population inversion, the number atoms in the ground state is …………. than the excited state.
a) higher b) lesser c) greater d) more
66. The life time of atoms in the excited state is normally ……………..
a) 10-6
second b) 10-3
second c) 10-8
second d) 10-10
second
67. The life time of atoms in the metastable state is normally ……………
a) 10-6
second b) 10-3
second c) 10-8
second d) 10-10
second
68. A ruby is a crystal of ……………. , in which of Al+3
ions are replaced by Cr+3
ions.
a) P2O5 b) Al2O6 c) Al2O2 d) Al2O3
69. The wavelength of green colour is ……………
a) 7500 Ao b) 5500 A
o c) 6943 A
o d) 6328A
o
…………… Continued in Page - 4
Page -4
70. The wavelength of red colour is ………………
a) 7500 Ao b) 5500 A
o c) 6943 A
o d) 6328A
o
71. He-Ne laser system consists of a quartz discharge containing helium and neon in the ratio of ….. at
a pressure of about 1 mm of Hg.
a) 4 : 1 b) 1 : 2 c) 1 : 4 d) 2 : 1
72. The wavelength of the emitted photon in the He-Ne laser system ……………..
a) 7500 Ao b) 5500 A
o c) 6943 A
o d) 6328A
o
73. The beam that is used in endoscopy is ……………….
a) laser b) maser c) ordinary light d) microwaves
74. The beam that is used in holography is ……………
a) laser b) maser c) ordinary light d) microwaves
75. The ……… action is based on the principle of population inversion followed by stimulated emission.
a) laser b) maser c) ordinary light d) microwaves
76. The ……………. ions are used as maser materials.
a) diamagnetic b) paramagnetic c) ferromagnetic d) aluminum
77. Practical maser materials are often ………………….. ions doped as impurities in ionic crystals.
a) chromium b) sodium c) potassium d) calcium
78. The ……………. is used in molecular spectroscopy.
a) laser b) maser c) ordinary light d) microwaves
79. In optical fiber, ……………. laser is used.
a) metal b) non-conducting c) semiconductor d) optical
80. The ratio of the radii of the first three orbits of an atom is ……………
a) 1 : 2 : 3 b) 1 : 3 : 5 c) 1 : 4 : 9 d) 1: 3 : 9
81. The cathode rays are a stream of …………….
a) protons b) photons c) electrons d) mesons
82. According to Bohr’s postulates, ……………. quantity take discrete values.
a) energy b) momentum c) radius d) angular momentum
83. For hydrogen atom, the minimum energy required to remove an electron from the first orbit to
the outermost orbit is …………. eV.
a) 13.6 b) 10.2 c) 5.4 d) infinity
84. According to Rutherford atom model, atoms will give only …………… spectrum.
a) continuous b) line c) band d) line absorption
85. The elliptical orbits of electron in the atom were proposed by …………….
a) Thomson b) Sommerfeld c) Roentgen d) Huygens
86. X ray is the phenomenon of conversion of kinetic energy into ……………
a) radiation b) potential energy c) magnetic d) electrostatic energy
87. The chromium ions doped in the ruby rod absorbs …………… light.
a) red b) blue c) green d) yellow
88. Canal rays travel …………. than the cathode rays.
a) slower b) faster c) higher speed d) none of the above
89. The spectra of alkali metals such as K, Na etc cannot be explained by ……………. atom model.
a) Thomson b) Sommerfeld c) Roentgen d) Huygens
90. In laser, all the photons are in …………. with each other.