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Set 3 of 16 · Questions 61-90 of 453

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Mere Teacher · Previous Year Questions JEE Main Physics · Atoms · Set 3 (Q61-90)
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61. $When a uranium isotope_{92}^{235} U is bombarded with a neutron, it generates_{36}^{89} Kr, three neutrons and [NEET 2020]$ (1) $_{40}^{91} Zr$ (2) $_{36}^{101} Kr$ (3) $_{36}^{103} Kr$ (4) $_{56}^{144} Ba$ 62. $The de Broglie wavelength of an electron in 4^{th} orbit is (r = radius of 1^{st} orbit)$ (1) $2 πr$ (2) $4 πr$ (3) $8 πr$ (4) $16 πr$ 63. $A radiation of energy ' E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C = Velocity of light):$ (1) $\frac{2 E}{C}$ (2) $\frac{2 E}{C ^{2}}$ (3) $\frac{E}{C ^{2}}$ (4) $\frac{E}{C}$ 64. $Find the ratio of energies of photons produced due to transition of an election of hydrogen atom from its (i) second permitted energy level to the first level, and (ii) the highest permitted energy level to the first permitted level.$ (1) $3 : 4$ (2) $4 : 3$ (3) $1 : 4$ (4) $4 : 1$ 65. $In Balmer series, wavelength of first line is λ_{1} and in Brackett series wavelength of first line is λ_{2}, then λ_{1} / λ_{2} is$ (1) $0.162$ (2) $0.124$ (3) $0.138$ (4) $0.188$ 66. $For a nucleus of mass number A and radius R, the mass density of nucleus can be represented as$ (1) $A^{\frac{2}{3}}$ (2) $Independent of A$ (3) $A^{3}$ (4) $A^{\frac{1}{3}}$ 67. $In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by:$ (1) $increasing the potential difference between the anode and filament$ (2) $increasing the filament current$ (3) $decreasing the filament current$ (4) $decreasing the potential difference between the anode and filament$ 68. $The ionization energy of hydrogen atom is 13.6 eV . Following Bohr’s theory, the energy corresponding to a transition between 3^{rd} and 4^{th} orbit is$ (1) $3.40 eV$ (2) $1.51 eV$ (3) $0.85 eV$ (4) $0.66 eV$ 69. $If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength λ . When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be [NEET 2016]$ (1) $\frac{16}{25} λ$ (2) $\frac{9}{16} λ$ (3) $\frac{20}{7} λ$ (4) $\frac{20}{13} λ$ 70. $In terms of Bohr radius a_{0}, the radius of the second Bohr orbit of a hydrogen atom is given by$ (1) $4 a_{0}$ (2) $8 a_{0}$ (3) $2 a_{0}$ (4) $2 a_{0}$ 71. $For the hydrogen atom, the energy of radiation emitted in the transition from 4^{th} excited state to 2^{nd} excited state, according to Bohr's theory is$ (1) $0.567 eV$ (2) $0.667 eV$ (3) $0.967 eV$ (4) $1.267 eV$ 72. $The total energy of an electron in an atom in an orbit is -3.4 eV. Its kinetic and potential energies are, respectively [NEET 2019]$ (1) $- 3.4 eV, - 6.8 eV$ (2) $3.4 eV, - 6.8 eV$ (3) $3.4 eV, 3.4 eV$ (4) $- 3.4 eV, - 3.4 eV$ 73. $In Raman effect, Stoke's lines are spectral lines having$ (1) $frequency greater than that of the original line$ (2) $wavelength equal to that of the original line$ (3) $wavelength less than that of the original line$ (4) $wavelength greater than that of the original line.$ 74. $If M_{o} is the mass of isotope_{5}^{12} B, M_{P} and M_{n} are the masses of proton and neutron, then nuclear binding energy of isotope is:$ (1) $(M_{o} - 5 M_{p}) C^{2}$ (2) $(5 M_{p} + 7 M_{n} - M_{o}) C^{2}$ (3) $(M_{0} - 12 M_{n}) C^{2}$ (4) $(M_{o} - 5 M_{p} - 7 M_{n}) C^{2}$ 75. $An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be (m is the mass of the electron, R, Rydberg constant and h Planck’s constant)$ (1) $\frac{24 hR}{25 m}$ (2) $\frac{25 hR}{24 m}$ (3) $\frac{25 m}{24 hR}$ (4) $\frac{24 m}{25 hR}$ 76. $For the given reaction, the particle X is_{6} C^{11} \to_{5} B^{11} + β^{+} + X$ (1) $neutron$ (2) $anti neutrino$ (3) $neutrino$ (4) $proton.$ 77. $The minimum excitation energy of an electron revolving in the first orbit of hydrogen is$ (1) $3.4 e v$ (2) $8.5 eV$ (3) $10.2 eV$ (4) $13.6 eV$ 78. $When a hydrogen atom is raised from the ground state to an excited state,$ (1) $both K.E. and P.E. increase$ (2) $both K.E. and P.E. decrease$ (3) $the P.E. decreases and K.E. increases$ (4) $the P.E. increases and K.E. decreases.$ 79. $Statement-I: When ultraviolet light is incident on a photocell, its stopping potential is V_{0} and the maximum kinetic energy of the photoelectrons is K_{max} . When the ultraviolet light is replaced by X-rays, both V_{0} and K_{max} increase. Statement-II: Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light.$ (1) $Statement-I is true, Statement-II is true; Statement-II is the correct explanation of Statement-I.$ (2) $Statement-1 is true, Statement-II is true; Statement-II is not the correct explanation of Statement-I$ (3) $Statement-I is false, Statement-II is true.$ (4) $Statement-I is true, Statement-II is false.$ 80. $When a neutron is disintegrated to give a β -particle,$ (1) $a neutrino alone is emitted$ (2) $a proton and neutrino are emitted$ (3) $a proton alone is emitted$ (4) $a proton and an antineutrino are emitted.$ 81. $If an electron in a hydrogen atom jumps from an orbit of level n = 3 to orbit of level n = 2, then the emitted radiation frequency is (where R = Rydberg's constant, C = Velocity of light)$ (1) $\frac{3 RC}{27}$ (2) $\frac{RC}{25}$ (3) $\frac{8 RC}{9}$ (4) $\frac{5 RC}{36}$ 82. $The frequencies for series limit of Balmer and Paschen series respectively are v_{1} and v_{3} . If frequency of first line of Balmer series is v_{2} then the relation between v_{1}, v_{2} and v_{3} is$ (1) $v_{1} - v_{2} = v_{3}$ (2) $v_{1} + v_{3} = v_{2}$ (3) $v_{1} + v_{2} = v_{3}$ (4) $v_{1} - v_{3} = 2 v_{1}$ 83. $A nucleus represented by the symbol_{Z}^{A} X has$ (1) $Z neutrons and A - Z protons$ (2) $Z protons and A - Z neutrons$ (3) $Z protons and A neutrons$ (4) $A protons and Z - A neutrons$ 84. $In a system, a particle A of mass m and charge - 2 q is moving in the nearest orbit around a very heavy particle B having charge + q . Assuming Bohr's model of the atom to be applicable to this system, the orbital angular velocity of the particle A is$ (1) $\frac{2 π m ^{2} q ^{2}}{ϵ _{0} h ^{4}}$ (2) $\frac{3 π m ^{3} q ^{2}}{ϵ _{0}^{3} h ^{2}}$ (3) $\frac{2 πm q ^{4}}{ϵ _{0}^{2} h ^{3}}$ (4) $\frac{5 π m ^{2} q ^{3}}{ϵ _{0}^{3} h ^{2}}$ 85. $In hydrogen spectrum, if the shortest wavelength in Balmer series is λ, the shortest wavelength in Brackett series is$ (1) $λ$ (2) $λ /2$ (3) $4 λ$ (4) $9 λ$ 86. $In a Frank-Hertz experiment, an electron of energy 5.6 eV passes through mercury vapour and emerges with an energy 0.7 eV. The minimum wavelength of photons emitted by mercury atoms is close to :$ (1) $1700 nm$ (2) $220 nm$ (3) $2020 nm$ (4) $250 nm$ 87. $An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photoelectron is 10 V, the value of n is:$ (1) $3$ (2) $4$ (3) $5$ (4) $2$ 88. $The wavelength of the radiation emitted is λ_{0} when an electron jumps from the second excited state to the first excited state of hydrogen atom. If the electron jumps from the third excited state to the second orbit of the hydrogen atom, the wavelength of the radiation mitted will be \frac{20}{x} λ_{0} . The value of x is _______.$ 89. $In Franck-Hertz experiment, the first dip in the current-voltage graph for hydrogen is observed at 10.2 V . The wavelength of light emitted by hydrogen atom when excited to the first excitation level is ______nm . (Given hc (= 1245 eVnm, e = 1.6 \times 10^{- 19} C) .$ 90. $A common example of alpha decay is_{92}^{238} U \to_{90}^{234} Th +_{2} He^{4} + Q Given:_{92}^{238} U = 238.05060 u_{90}^{234} Th = 234.04360 u_{2}^{4} He = 4.00260 u and 1 u = 931.5 \frac{MeV}{c ^{2}} The energy released (Q) during the alpha decay of^{238}_{92} U is____MeV.$