Tiêu đề 12. ATOMS.pdf ✅

Answer Key (1) the first member of the Lyman series, thrid line of Balmer series and second line of Paschen series. (2) the ionisation po- tential of , second line of Balmer series and third line of Paschen series. (3) the series limit of Lyman series, second line of Balmer series and second of line Paschen series. (4) the series limit of Lyman series, third line of Balmer series and second line of Paschen series. 34. An electron in a hydrogen atom makes a transi‐ tion from first excited state to ground state. The equivalent current due to circulating electron: (1) increasing 2 times (2) increases 4 times (3) increases 8 times (4) remains the same 35. If the speed of an electron of hydrogen atom in the ground state is , then its speed in the third excited state will be (1) (2) (3) (4) 36. The value of ground state energy of a -atom is . The energy required to take an electron from ground state to the first excited state is: (1) (2) (3) (4) 37. When an particle of mass moving with velocity bombards on a heavy nucleus of charge , its distance of closest approach from the nucleus depends on as: (1) (2) (3) (4) 38. Orbital acceleration of electron is (1) (2) (3) (4) 39. Assertion : Standard optical diffraction cannot be used for discriminating between different ray wave‐ lengths. Reason : The grating spacing is not of the order of -ray wavelengths (1) Both Assertion and Reason are cor- rect and Reason is the correct explana- tion of the Assertion. (2) Both Assertion and Reason are cor- rect but Reason is not the correct explana- tion of the Assertion. (3) Assertion is cor- rect but Reason is incorrect. (4) Both Assertion and Reason are incorrect. 40. In case of a hydrogen atom the ratio of areas of electrons orbits corresponding to first excited state and ground state is (1) (2) (3) (4) 41. Hydrogen atom from excited state comes to the ground state by emitting a photon of wavelength .If is the Rydberg constant, the principal quantum number of the excited state is (1) (2) (3) (4) 42. Angular momentum and radius of a hy‐ drogen atom are related as: (1) (2) (3) (4) 43. Ionisation energy of a hydrogen-like ion is greater than that of another hydrogen like ion . If and represent atomic numbers of and then (1) (2) (3) (4) 44. The ground state energy of hydrogen atom is . The kinetic energy of the electron in this state is: (1) (2) (3) (4) 45. The energy of hydrogen atom in ground state is The ionisation energy of singly ionised helium will be (1) (2) (3) (4) H 2.2 × 10 6m/s 5.5 × 10 6m/s 5.5 × 10 5m/s 8.8 × 10 5m/s 6.8 × 10 6m/s H −13.6 eV −10.2 eV +10.2 eV −17 eV −3.4 eV α− ′m′ ′v ′ ′Ze ′ m 1 m 1 √m 1 m2 m 4n 2h 2 π 2m2r 3 n 2h 2 4π 2m2r 3 4n 2h 2 4π 2m2r 3 n 2h 2 2n 2r 3 X X 16 : 1 18 : 1 4 : 1 2 : 1 λ R n √ λR λR−1 √ λ λR−1 √ λR2 λR−1 √ λR λ−1 (L) (r) Lr = constant Lr 2 = constant Lr 4 = constant None of these A B ZA ZB A B ZB > ZA ZA > ZB ZA = ZB Can ′tbepredicted −13.6eV 1.85 eV 13.6 eV 6.8 eV 3.4 eV 13.6 eV He 2+ 13.6 eV 3.4 eV 27.2 eV 54.4 eV