Atoms PYQs Set 10 (PDF)

Set 10 of 14 · Questions 271-300 of 394

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Mere Teacher · Previous Year Questions NEET Physics · Atoms · Set 10 (Q271-300)
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271. $A hydrogen atom in is ground state absorbs 10.2 eV of energy. The angular momentum of electron of the hydrogen atom will increase by the value of: (Given, Plank's constant = 6.6 x 1 0^{- 34} Js)$ (1) $2.10 x 1 0^{- 34} Js$ (2) $1.05 x 1 0^{- 34} Js$ (3) $3.15 x 1 0^{- 34} Js$ (4) $4.2 x 1 0^{- 34} Js$ 272. $After absorbing a slowly moving neutron of Mass m_{N} (momentum \approx 0) a nucleus of mass M breaks into two nuclei of masses m_{1} and 5 m_{1} (6 m_{1} = M + m_{N}) respectively. If the de Broglie wavelength of the nucleus with mass m_{1} is λ, the de Broglie wevelength of the nucleus will be:$ (1) $5 λ$ (2) $λ /5$ (3) $λ$ (4) $25 λ$ 273. $Assuming the validity of Bohr's atomic model for hydrogen like ions the radius of Li^{++} ion in its ground state is given by \frac{1}{X} a_{0}, where X =_______ (Where a_{0} is the first Bohr's radius.)$ (1) $2$ (2) $9$ (3) $1$ (4) $3$ 274. $A 12. 5 eV electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be:$ (1) $1$ (2) $4$ (3) $2$ (4) $3$ 275. $Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelength λ_{1} : λ_{2} emitted in the two cases is$ (1) $7/5$ (2) $27/20$ (3) $27/5$ (4) $20/7$ 276. $Match the following two columns. NEET 2024] Column I (Spectral lines of Hydrogen for transitions from) (A) n_{2} = 3 to n1=2 (B) n_{2} = 4 to n1=2 (C) n_{2} = 5 to n1=2 (D) n_{2} = 6 to n1=2 Column II (Wavelengths (nm)) (I) 410.2 (II) 434.1 (III) 656.3 (IV) 486.1 Choose the correct answer from the options given below.$ (1) $A-II, B-I, C-IV, D-III$ (2) $A-III, B-IV, C-II, D-I$ (3) $A-IV, B-III, C-I, D-II$ (4) $A-I, B-II, C-III, D-IV$ 277. $Total energy of electron in an excited state of hydrogen atom is - 3.4 eV . The kinetic and potential energy of electron in this state$ (1) $K = - 3.4 eV U=-6.8eV$ (2) $K = 3.4 eV U=-6.8eV$ (3) $K = - 6.8 eV U = + 3.4 eV$ (4) $K = + 10.2 eV U = - 13.6 eV$ 278. $Of the following pairs of species which one will have the same electronic configuration for both members?$ (1) $L i^{+} and N a^{+}$ (2) $He and N e^{+}$ (3) $H and Li$ (4) $C and N^{+}$ 279. $For which one of the following, Bohr model is not valid? [NEET 2020]$ (1) $Singly ionised helium atom (He^{+})$ (2) $Deuteron atom$ (3) $Singly ionised neon atom (Ne^{+})$ (4) $Hydrogen atom$ 280. $Given the value of Rydberg constant is 10^{7} m^{- 1}, the wave number of the last line of the Balmer series in hydrogen spectrum will be:$ (1) $2.5 \times 10^{7} m^{- 1}$ (2) $0.025 \times 10^{4} m^{- 1}$ (3) $0.5 \times 10^{7} m^{- 1}$ (4) $0.25 \times 10^{7} m^{- 1}$ 281. $Two radioactive elements A and B initially have same number of atoms. The half life of A is same as the average life of B. If λ_{A} and λ_{B} are decay constants of A and B respectively, then choose the correct relation from the given options.$ (1) $λ_{A} ln 2 = λ_{B}$ (2) $λ_{A} = λ_{B}$ (3) $λ_{A} = λ_{B} ln 2$ (4) $λ_{A} = 2 λ_{B}$ 282. $The period of revolution of an electron in the ground state of hydrogen atom is T . The period of revolution of the electron in the first excited state is$ (1) $2 T$ (2) $4 T$ (3) $6 T$ (4) $8 T$ 283. $If λ_{1} and λ_{2} are the wavelengths of the first nembers of the Lyman and Paschen series respectively, then λ_{1} : λ_{2} is$ (1) $1 : 3 q$ (2) $1 : 30$ (3) $7 : 50$ (4) $7 : 108$ 284. $An α -particle of energy 5 MeV is scattered through 180^{\circ} by gold nucleus. The distance of closest approach is of the order of$ (1) $10^{- 12} cm$ (2) $10^{- 16} cm$ (3) $10^{- 10} cm$ (4) $10^{- 14} cm$ 285. $Magnetic field at the centre of the hydrogen atom due to motion of electrons in n^{th} orbit is proportional to$ (1) $n^{4}$ (2) $n^{- 3}$ (3) $n^{3}$ (4) $n^{- 5}$ 286. $The energy equivalent of 1 g of substance is :$ (1) $5.6 \times 10^{12} MeV$ (2) $5.6 \times 10^{26} MeV$ (3) $11.2 \times 10^{24} MeV$ (4) $5.6 eV$ 287. $Let T_{1} and T_{2} be the energy of an electron in the first and second excited states of hydrogen atom, respectively. According to the Bohr's model of an atom, the ratio of T_{1} : T_{2} is [NEET 2022]$ (1) $4 : 1$ (2) $4 : 9$ (3) $9 : 4$ (4) $1 : 4$ 288. $The light emitted in the transition n = 3 to n = 2 (where n is the principal quantum number of the state) in hydrogen is called H_{α} -light. Find the maximum work function that a metal can have so that H_{α} -light can emit photoelectrons from it.$ (1) $1.5 eV$ (2) $2.89 eV$ (3) $1.89 eV$ (4) $3.5 eV$ 289. $In a hydrogen like atom, when an electron jumps from the M-shell to the L-shell, the wavelength of emitted radiation is λ . If an electron jumps from N-shell to eh L-shell, the wavelength of emitted radiation will be:$ (1) $\frac{27}{20} λ$ (2) $\frac{16}{25} λ$ (3) $\frac{25}{16} λ$ (4) $\frac{20}{27} λ$ 290. $The Q-value of a nuclear reaction and kinetic energy of the projectile particle, K_{p} are related as:$ (1) $Q = K_{P}$ (2) $(K_{P} + Q) < 0$ (3) $Q < K_{P}$ (4) $(K_{P} + Q) > 0$ 291. $Continuous emission spectrum is produced by$ (1) $incandescent electric lamp$ (2) $mercury vapour lamp$ (3) $sodium vapour lamp$ (4) $the sun.$ 292. $A photon is emitted in transition from n = 4 to n = l level in hydrogen atom. The corresponding wavelength for this transition is (given, h = 4 x 1 0^{- 15} eVs):$ (1) $94.1 nm$ (2) $941 nm$ (3) $97.4 nm$ (4) $993 nm$ 293. $Frequency of the series limit of Balmer series of hydrogen atom in terms of Rydberg's constant (R) and velocity of light (c) is$ (1) $4 Rc$ (2) $\frac{4}{Rc}$ (3) $Rc$ (4) $\frac{Rc}{4}$ 294. $If the electron in hydrogen atom jumps from second Bohr orbit to ground state and difference between energies of the two states is radiated in the form photons. If the work function of the material is 4.2 eV then stopping potential is [Energy of electron in n^{th} orbit = - \frac{13.6}{n ^{2}} eV]$ (1) $2 eV$ (2) $4 eV$ (3) $6 eV$ (4) $8 eV$ 295. $A radioactive nucleus n_{2} has 3 times the decay constant as compared to the decay constant of another radioactive nucleus n_{1} . If initial number of both nuclei are the same, what is the ratio of number of nuclei of n_{2} to the number of nuclei of n_{1}, after one half-life of n_{1} ?$ (1) $1/8$ (2) $8$ (3) $4$ (4) $1/4$ 296. $If the de-Broglie wavelength of an electron is equal to 10^{- 3} times the wavelength of a photon of frequency 6 \times 10^{14} Hz, then the speed of electron is equal to: (Speed of light = 3 \times 10^{8} m / s, Planck's constant= 6.63 \times 10^{- 34} J . s Mass of electron = 9.1 \times 10^{- 31} kg)$ (1) $1.7 \times 10^{6} m / s$ (2) $1.45 \times 10^{6} m / s$ (3) $1.8 \times 10^{6} m / s$ (4) $1.1 \times 10^{6} m / s$ 297. $The ratio of radii of 3^{rd} and 6^{th} Bohr's orbit in a hydrogen atorn is$ (1) $0.25$ (2) $0.33$ (3) $4$ (4) $3$ 298. $The magnetic filed associated with a light wave is given, at the origin, by B = B_{0} (sin (3.14 \times 10^{7}) ct + sin (6.28 \times 10^{7}) ct) . If this light falls on a sliver pate having a work function of 4.7 eV , what will be the maximum kinetic energy of the photo electrons? (c = 3 \times 10^{8} ms^{- 1}, h = 6.6 \times 10^{- 34} J - s)$ (1) $6.82 eV$ (2) $12.5 eV$ (3) $7.72 eV$ (4) $8.52 eV$ 299. $In L i^{++}, electron in first Bohr orbit is excited to a level by a radiation of wavelength λ . When the ion gets deexcited to the ground state in all possible ways (including intermediate emissions), a total of six spectral lines are observed. What is the value of λ ? (Given: h = 6.63 \times 10^{- 34} Js; c = 3 \times 10^{8} m s^{- 1})$ (1) $11.4 nm$ (2) $9.4 nm$ (3) $12.3 nm$ (4) $10.80 nm$ 300. $The smallest wavelength of Lyman series is 91 nm. The difference between the largest wavelengths of Paschen and Balmer series is nearly____nm.$ (1) $1550$ (2) $1217$ (3) $1875$ (4) $1784$