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Mere Teacher · Previous Year Questions NEET Physics · Atoms · Set 3 (Q61-90)
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61. $The ionization energy of hydrogen atom is 13.6 eV . Following Bohr’s theory, the energy corresponding to a transition between 3^{rd} and 4^{th} orbit is$ (1) $3.40 eV$ (2) $1.51 eV$ (3) $0.85 eV$ (4) $0.66 eV$ 62. $If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength λ . When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be [NEET 2016]$ (1) $\frac{16}{25} λ$ (2) $\frac{9}{16} λ$ (3) $\frac{20}{7} λ$ (4) $\frac{20}{13} λ$ 63. $In terms of Bohr radius a_{0}, the radius of the second Bohr orbit of a hydrogen atom is given by$ (1) $4 a_{0}$ (2) $8 a_{0}$ (3) $2 a_{0}$ (4) $2 a_{0}$ 64. $For the hydrogen atom, the energy of radiation emitted in the transition from 4^{th} excited state to 2^{nd} excited state, according to Bohr's theory is$ (1) $0.567 eV$ (2) $0.667 eV$ (3) $0.967 eV$ (4) $1.267 eV$ 65. $The total energy of an electron in an atom in an orbit is -3.4 eV. Its kinetic and potential energies are, respectively [NEET 2019]$ (1) $- 3.4 eV, - 6.8 eV$ (2) $3.4 eV, - 6.8 eV$ (3) $3.4 eV, 3.4 eV$ (4) $- 3.4 eV, - 3.4 eV$ 66. $In Raman effect, Stoke's lines are spectral lines having$ (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) $wavelength greater than that of the original line.$ 67. $If M_{o} is the mass of isotope_{5}^{12} B, M_{P} and M_{n} are the masses of proton and neutron, then nuclear binding energy of isotope is:$ (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) $(M_{o} - 5 M_{p} - 7 M_{n}) C^{2}$ 68. $An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be (m is the mass of the electron, R, Rydberg constant and h Planck’s constant)$ (1) $\frac{24 hR}{25 m}$ (2) $\frac{25 hR}{24 m}$ (3) $\frac{25 m}{24 hR}$ (4) $\frac{24 m}{25 hR}$ 69. $For the given reaction, the particle X is_{6} C^{11} \to_{5} B^{11} + β^{+} + X$ (1) $neutron$ (2) $anti neutrino$ (3) $neutrino$ (4) $proton.$ 70. $The minimum excitation energy of an electron revolving in the first orbit of hydrogen is$ (1) $3.4 e v$ (2) $8.5 eV$ (3) $10.2 eV$ (4) $13.6 eV$ 71. $When a hydrogen atom is raised from the ground state to an excited state,$ (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) $the P.E. increases and K.E. decreases.$ 72. $Statement-I: When ultraviolet light is incident on a photocell, its stopping potential is V_{0} and the maximum kinetic energy of the photoelectrons is K_{max} . When the ultraviolet light is replaced by X-rays, both V_{0} and K_{max} increase. Statement-II: Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light.$ (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) $Statement-I is true, Statement-II is false.$ 73. $When a neutron is disintegrated to give a β -particle,$ (1) $a neutrino alone is emitted$ (2) $a proton and neutrino are emitted$ (3) $a proton alone is emitted$ (4) $a proton and an antineutrino are emitted.$ 74. $If an electron in a hydrogen atom jumps from an orbit of level n = 3 to orbit of level n = 2, then the emitted radiation frequency is (where R = Rydberg's constant, C = Velocity of light)$ (1) $\frac{3 RC}{27}$ (2) $\frac{RC}{25}$ (3) $\frac{8 RC}{9}$ (4) $\frac{5 RC}{36}$ 75. $The frequencies for series limit of Balmer and Paschen series respectively are v_{1} and v_{3} . If frequency of first line of Balmer series is v_{2} then the relation between v_{1}, v_{2} and v_{3} is$ (1) $v_{1} - v_{2} = v_{3}$ (2) $v_{1} + v_{3} = v_{2}$ (3) $v_{1} + v_{2} = v_{3}$ (4) $v_{1} - v_{3} = 2 v_{1}$ 76. $A nucleus represented by the symbol_{Z}^{A} X has$ (1) $Z neutrons and A - Z protons$ (2) $Z protons and A - Z neutrons$ (3) $Z protons and A neutrons$ (4) $A protons and Z - A neutrons$ 77. $In a system, a particle A of mass m and charge - 2 q is moving in the nearest orbit around a very heavy particle B having charge + q . Assuming Bohr's model of the atom to be applicable to this system, the orbital angular velocity of the particle A is$ (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) $\frac{5 π m ^{2} q ^{3}}{ϵ _{0}^{3} h ^{2}}$ 78. $In hydrogen spectrum, if the shortest wavelength in Balmer series is λ, the shortest wavelength in Brackett series is$ (1) $λ$ (2) $λ /2$ (3) $4 λ$ (4) $9 λ$ 79. $In a Frank-Hertz experiment, an electron of energy 5.6 eV passes through mercury vapour and emerges with an energy 0.7 eV. The minimum wavelength of photons emitted by mercury atoms is close to :$ (1) $1700 nm$ (2) $220 nm$ (3) $2020 nm$ (4) $250 nm$ 80. $An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photoelectron is 10 V, the value of n is:$ (1) $3$ (2) $4$ (3) $5$ (4) $2$ 81. $The energy (in eV) required to excite an electron from n = 2 to n = 4 state in hydrogen atom$ (1) $+2.55$ (2) $-3.4$ (3) $+4.25$ (4) $-0.85$ 82. $If an electron is moving in the 4^{th} orbit of the hydrogen atom then the angular momentum of the electron in SI units is$ (1) $\frac{h}{π}$ (2) $\frac{2 h}{π}$ (3) $\frac{4 h}{π}$ (4) $\frac{h}{2 π}$ 83. $A radio active material is reduced to \frac{1}{8} of its original amount in 3 days. If 8 x 10-3 kg of the material is left after 5 days the initial amount of the material is$ (1) $40 g$ (2) $32 g$ (3) $64 g$ (4) $256 g$ 84. $The radiation corresponding to 3 \to 2 transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of 3 \times 10^{- 4} T . If the radius of the largest circular path followed by these electrons is 10.0 mm , the work function of the metal is close to :$ (1) $1.8 eV$ (2) $1.1 eV$ (3) $0.8 eV$ (4) $1.6 eV$ 85. $Choose the correct nuclear process from the below options [ p : proton, n : neutron, e^{-} : electron, e^{+} : positron, v : neutrino, v : antineutrino]$ (1) $n \to p + e^{+} + v$ (2) $p\ton+e++v$ (3) $p\ton+e-+v$ (4) $n \to p + e^{-} + v$ 86. $If the first line of Lyman series has a wavelength 1215.4Å, the first line of Balmer series is approximately$ (1) $4864Å$ (2) $1025.5Å$ (3) $6563Å$ (4) $6400Å$ 87. $If the radius of the first Bohr orbit is ' r' then the de-Broglie wavelength of the electron in the 4^{th} orbit will be$ (1) $4 πr$ (2) $6 πr$ (3) $8 πr$ (4) $\frac{πr}{4}$ 88. $When an electron does transition from n = 4 to n = 2, then emitted line spectrum will be$ (1) $first line of Lyman series$ (2) $second line of Balmer series$ (3) $first line of Paschen series$ (4) $second line of Paschen series$ 89. $A hydrogen atom at the ground level absorbs a photon and is excited to n = 4 level. The potential energy of the electron in the excited state is$ (1) $- 0.85 eV$ (2) $+ 0.85 eV$ (3) $- 1.7 eV$ (4) $+ 1.7 eV$ 90. $The half life period of a radioactive substance is 60 days. The time taken for \frac{7}{8} th of its original mass to disintegrate will be:$ (1) $120 days$ (2) $130 days$ (3) $180 days$ (4) $20 days$