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Set 4 of 14 · Questions 91-120 of 394

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Mere Teacher · Previous Year Questions NEET Physics · Atoms · Set 4 (Q91-120)
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91. $The ground state energy of H ‐atom is 13.6 eV The energy needed to ionize H ‐atom from its second excited state$ (1) $1.51 eV$ (2) $3.4 eV$ (3) $13.6 eV$ (4) $none of these$ 92. $The disintegration rate of a certain radioactive sample at any instant is 4250 disintegrations per minute. 10 minutes later, the rate becomes 2250 disintegrations per minute. The approximate decay constant is: (Take l o g_{10} l.88 = 0.274)$ (1) $0.02 mi n^{- 1}$ (2) $2.7 mi n^{- 1}$ (3) $0.063 mi n^{- 1}$ (4) $6.3 mi n^{- 1}$ 93. $A photon released by the transition of an electron from the second excited state to the ground state of Hydrogen atom is incident on the surface of a metal of work function 3.1 eV . The de Broglie wavelength of the most energetic electron emitted from that metal surface is nearly$ (1) $2.6Å$ (2) $4Å$ (3) $6Å$ (4) $None$ 94. $A particle is moving 5 times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of the electron is 1.878 \times 10^{- 4} . The mass of the particle is close to:$ (1) $1.2 \times 10^{- 28} kg$ (2) $9.1 \times 10^{- 31} kg$ (3) $4.8 \times 10^{- 27} kg$ (4) $9.7 \times 10^{- 28} kg$ 95. $In ruby laser, the stimulated emission is due to transition from$ (1) $metastable state to any lower state$ (2) $any higher state to lower state$ (3) $metastable state to ground state$ (4) $any higher state to ground state.$ 96. $The de-Broglie wavelength of the electron in the ground state of the hydrogen atom is (radius of the first orbit of hydrogen atom = 0.53Å).$ (1) $1.67Å$ (2) $3.33Å$ (3) $1.06Å$ (4) $0.53Å$ 97. $The ratio of the magnetic dipole moment to the angular momentum of the electron in the 1^{st} orbit of hydrogen atom is$ (1) $e /2 m$ (2) $e / m$ (3) $2 m / e$ (4) $m / e$ 98. $Energy of a stationary electron in the hydrogen atom is E = - \frac{13.6}{n ^{2}} eV then the energies required to excite the electron in hydrogen atom to (i) its second excited state and (ii) ionized state respectively$ (1) $(i) \sim 10 eV, (ii) 13.6eV$ (2) $(i) \sim 12 eV, (ii) 13.6 eV$ (3) $(i) \sim12eV, (ii) 10.6 eV$ (4) $(i) \sim 8 eV, (ii) 13.6eV$ 99. $In a nuclear fission reaction of an isotope of mass M, three similar daughter nuclei of same mass are formed. The speed of a daughter nuclei in terms of mass defect Δ M will be :$ (1) $\frac{2 c Δ M}{M}$ (2) $\frac{Δ Mc ^{2}}{3}$ (3) $c \frac{2Δ M}{M}$ (4) $c \frac{3Δ M}{M}$ 100. $Which level of the single ionized carbon has the same energy as the ground state energy of hydrogen atom?$ (1) $1$ (2) $6$ (3) $4$ (4) $8$ 101. $The ratio of longest wavelengths of the spectral lines in the Lyman and Balmer series of hydrogen spectrum is$ (1) $\frac{3}{23}$ (2) $\frac{5}{27}$ (3) $\frac{7}{29}$ (4) $\frac{9}{31}$ 102. $Choose the correct option from the following options given below:$ (1) $In the ground state of Rutherford's model electrons are in stable equilibrium. While in Thomson's model electrons always experience a net-force.$ (2) $An atom has a nearly continuous mass distribution in a Rutherford's model but has a highly non-uniform mass distribution in Thomson's model$ (3) $A classical atom based on Rutherford's model is doomed to collapse.$ (4) $The positively charged part of the atom possesses most of the mass in Rutherford's model but not in Thomson's model.$ 103. $The collision of an electron with kinetic energy 5.5 eV and a hydrogen atom in its ground state can be described as$ (1) $completely inelastic$ (2) $may be completely inelastic$ (3) $may be partially elastic$ (4) $elastic$ 104. $The period of revolution of an electron revolving in n^{th} orbit of H -atom is proportional to$ (1) $n^{3}$ (2) $independent of n$ (3) $n^{2}$ (4) $1/ n$ 105. $The radius of third stationary orbit of electron for Bohr's atom is R . The radius of fourth stationary orbit will be:$ (1) $\frac{4}{3} R$ (2) $\frac{16}{9} R$ (3) $\frac{3}{4} R$ (4) $\frac{9}{16} R$ 106. $Angular momentum of an electron in hydrogen atom is 3 h /2 π (h is the Planck's constant). The K.E. of the electron is$ (1) $3.4 eV$ (2) $6.8 eV$ (3) $4.35 eV$ (4) $1.51 eV$ 107. $Bohr model is applied to a particle of mass ' m' and charge ' q' moving in a plane under the influence of a transverse magnetic field ' B'. The energy of the charged particle in the n^{th} level will be$ (1) $2 nhqB / πm$ (2) $nhqB /2 πm$ (3) $nhqB /4 πm$ (4) $nhqB / πm$ 108. $The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 α particles is____kHz . [mass of He nucleus = 4.002 amu, 1 amu = 1.66 \times 10^{- 27} kg, h = 6.6 \times 10^{- 34} J . s and c = 3 \times 10^{8} m / s]$ (1) $14.94 \times 10^{19}$ (2) $9 \times 10^{20}$ (3) $14.94 \times 10^{20}$ (4) $9 \times 10^{19}$ 109. $The ratio for the speed of the electron in the 3^{r d} orbit of H e^{+} to the speed of the electron in the 3^{r d} orbit of hydrogen atom will be:-$ (1) $1 : 1$ (2) $1 : 2$ (3) $4 : 1$ (4) $2 : 1$ 110. $An electron rotates in a circle around a nucleus having positive charge Ze . Correct relation between total energy (E) of electron to its potential energy (U) is:$ (1) $E = U$ (2) $2 E = U$ (3) $2 E = 3 U$ (4) $E = 2 U$ 111. $The ratio of longest wavelength lines in the Balmer and Paschen series of hydrogen spectrum is$ (1) $\frac{5}{36}$ (2) $\frac{7}{20}$ (3) $\frac{7}{144}$ (4) $\frac{5}{27}$ 112. $According to Bohr’s principle, the relation between principal quantum number (n) and radius of orbit (r) is$ (1) $r \propto \frac{1}{n}$ (2) $r \propto \frac{1}{n ^{2}}$ (3) $r \propto n$ (4) $r \propto n^{2}$ 113. $The volume occupied by an atom is greater than the volume of the nucleus by a factor of about$ (1) $1 0^{1}$ (2) $1 0^{5}$ (3) $1 0^{10}$ (4) $1 0^{15}$ 114. $The energy required to ionize a hydrogen like ion in its ground state is 9Rydbergs. What is the wavelength of the radiation emitted when the electron in this ion jumps from the second excited state to the ground state:$ (1) $24.2 nm$ (2) $6.8 nm$ (3) $35.8 nm$ (4) $11.4 nm$ 115. $In hydrogen spectrum, the shortest and longest wavelengths of Balmer series are λ_{1} and λ_{2} respectively. The Rydberg constant of hydrogen is$ (1) $\frac{1}{λ _{1}} - \frac{9}{λ _{2}}$ (2) $\frac{4}{λ _{1}} - \frac{9}{λ _{2}}$ (3) $\frac{9}{λ _{1}} - \frac{9}{λ _{2}}$ (4) $\frac{9}{λ _{1}} - \frac{4}{λ _{2}}$ 116. $In the hydrogen atom spectrum, let E_{1} and E_{2} are energies for the transition n = 2 \to n = 1 and n = 3 \to n = 2, respectively. The ratio E_{2} / E_{1} is$ (1) $\frac{2}{3}$ (2) $\frac{3}{2}$ (3) $\frac{2}{9}$ (4) $\frac{5}{27}$ 117. $Light emitted during the de excitation of electron from n = 3 to n = 2, when incident on a metal, photoelectrons are just emitted from that metal. In which of the following deexcitations photoelectric effect is not possible?$ (1) $From n = 2 to n = 1$ (2) $From n = 3 to n = 1$ (3) $From n = 5 to n=2$ (4) $From n = 4 to n=3$ 118. $The radius of orbit of an electron and the speed of electron in the ground state of hydrogen atom are 5.5 \times 10^{- 11} m and 4 \times 10^{6} ms^{- 1} respectively. Then, the orbital period of this electron in the first excited state will be\dots\dots\dots$ (1) $6.908 \times 10^{- 16} s$ (2) $9.608 \times 10^{- 16} s$ (3) $7.806 \times 10^{- 16} s$ (4) $8.9068 \times 10^{- 16} s$ 119. $The total energy of an electron in an atom in an orbit is - 3.4 eV Its kinetic and potential energies are, respectively$ (1) $3.4 eV, 3.4 eV$ (2) $- 3.4 eV, - 3.4 eV$ (3) $- 3.4 eV, - 6.8 eV$ (4) $3.4 eV, - 6.8 eV$ 120. $An electron in H-atom makes a transition from n = 3 to n = 1. The recoil momentum of H-atom will be-$ (1) $6.45 \times 1 0^{-27} N s$ (2) $6.8 \times 1 0^{-27} N s$ (3) $6.45 \times 1 0^{-24} N s$ (4) $6.8 \times 1 0^{-24} N s$