Atomic Structure-3

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66. The photoelectric effect is described as the ejection of electrons from the surface of a metal when—
(A) It is heated
(B) It is placed in strong electric field
(C) Electrons of suitable velocity impinges on it
(D) Light of suitable frequency falls on it
Ans. (D)

67. The photoelectric emission from metal surface starts only when the incident light has a certain minimum
(A) Wavelength (B) Velocity
(C) Frequency (D) Acceleration
Ans. (C)

68. Propagation of light quanta may be described by–
(A) Photons (B) Protons
(C) Neutrons (D) Electrons
Ans. (A)

69. The value of planck’s constant is—
(A) 6.62×10–34 J
(B) 6.62×10–34 J.s
(C) 6.62×10–34 erg.s
(D) None of these
Ans. (B)

70. If an electron and a photon have the same wavelength, then they will have the same
(A) Velocity
(B) Linear momentum
(C) Angular momentum
(D) Energy
Ans. (B)

71. Which of the following particle has the dual nature of particle and wave?
(A) Neutron
(B) Electron
(C) Meson
(D) Proton
Ans. (B)

72. The concept of dual nature of radiation was proposed by—
(A) Max planck
(B) De-Broglie
(C) Heisenberg
(D) Pauling
Ans. (B)

73. “The position and velocity of a small particle like electron can not be simultaneously determined. “This statement is—
(A) Heisenberg uncertainty principle
(B) Pauli’s exclusion principle
(C) Aufbau principle
(D) De-Broglie wave nature of electron
Ans. (A)

74. Who discovered X- Ray?
(A) Wilhelm Roentgen
(B) William Lee
(C) X Lollswick
(D) I Thompson
Ans. (A)

75. By which one of the following, an old written material which can not be read easily, can be
(A) – rays
(B) X – rays
(C) IR – rays
(D) Radio frequency waves
Ans. (B)

76. Which one of the following is the correct sequence of wavelength of radiations?
(A) UV > Green > IR > Hard X – rays
(B) IR > Green > UV > Hard X – rays
(C) UV > Hard X – rays > IR > Green
(D) IR > Hard X – rays > Green > UV
Ans. (B)

77. Which of the following is not Electromagnetic in nature?
(A) Cathode rays
(B) X – rays
(C) Gamma – rays
(D) Infrared – rays
Ans. (A)

78. Wavelength of which of the following colours of the visible spectrum of light are maximum
absorbed by green plants –
(A) Green and yellow
(B) Red and blue
(C) Green and red
(D) Blue and yellow
Ans. (B)

79. Which of the following is not true about X rays?
(A) Low power
(B) Travel with the speed of light
(C) Refracted
(D) Can affect photographic plates
Ans. (A)

80. The reverse effect of X-ray emission is
(A) Raman effect
(B) Compton effect
(C) Zeeman effect
(D) Photo-electric effect
Ans. (D)

81. Which of the following has the lowest frequency?
(A) Visible light
(B) Gamma rays
(C) X-rays
(D) Ultra violet rays
Ans. (A)

82. All isotopes of the same element have —
(A) Different atomic numbers and different atomic mass
(B) Different atomic numbers and the same atomic mass
(C) The same atomic number but different atomic mass
(D) The same atomic number and the same atomic mass
Ans. (C)

83. Nuclides have same atomic number are called:
(A) Isotopes
(B) Isobar
(C) Isotones
(D) Isoelectrons
Ans. (A)

84. Atoms of same element having different mass numbers are called —
(A) Isobars
(B) Isotopes
(C) Isotones
(D) Isomers
Ans. (B)

85. Chemical properties of isotopes
(A) Must be Same
(B) Must be Different
(C) Need not be Same
(D) Need not be Different
Ans. (A)

86. Atoms having the same number of protons but different number of neutrons are called:
(A) Isotopes
(B) Cations
(C) Higgs-boson
(D) Anions
Ans. (A)

87. Atoms of different elements have
(A) Same atomic number and same electronic configuration
(B) Different atomic number and same electronic configuration
(C) Different atomic number and different number of valence electrons
(D) Same number of electrons and neutrons
Ans. (C)

88. Atoms having same no of neutron but different no of electrons or protons are called–
(A) Isotopes
(B) Isobars
(C) Isotones
(D) Allotropes
Ans. (C)

89. 40Ar18 40K19 40Ca20 are called –
(A) Isotones
(B) Isotopes
(C) Isobars
(D) None
Ans. (C)

90. Isobars have –
(A) Same mass numbers but different atomic numbers
(B) Different mass numbers but same atomic numbers
(C) Same mass and atomic numbers
(D) Different mass and atomic numbers
Ans. (A)

91. Who was the first to explain hydrogen spectrum?
(A) Dalton
(B) Neil Bohr
(C) Rutherford
(D) J.J. Thomson
Ans. (B)

92. Bohr’s model can explain :
(A) Spectrum of hydrogen atom only
(B) Spectrum of any atom or ion having one electron only
(C) Spectrum of hydrogen molecule
(D) Solar spectrum
Ans. (B)

93. The value of Bohr radius of hydrogen atom is
(A) 0.529 × 10–7 cm
(B) 0.529 × 10–8 cm
(C) 0.529 × 10–9 cm
(D) 0.529 × 10–10 cm
Ans. (B)

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