Title 02. STRUCTURE OF ATOM - 01.pdf ✅

1 JEE ADVANCED 2024 Atomic Structure Single Correct (1 – 9) 1. The vapours of Hg absorb some electron accelerated by a potential difference of 5.0 V as a result of which light is emitted. If the full energy of single incident electron is supposed to be converted into light emitted by single Hg-atom, then the wavelength of the emitted light is (1) 2480 nm (2) 248 nm (3) 6200 nm (4) 620 nm 2. A ruby laser produces radiations of wavelength 662.6 nm in pulses whose duration are 1.0 × 10–9 s. If the laser produces 0.36 J of energy per pulse, then how many photons are produced in each pulse? (1) 1.2 × 109 (2) 1.2 × 1027 (3) 1.2 × 1018 (4) 1.2 × 1015 3. Light of wavelength (λ) strikes a metal surface with intensity X and the metal emits Y electrons per second of maximum kinetic energy Z. What will happen to Y and Z if X is halved? (1) Y will be halved and Z will be doubled. (2) Y will be doubled and Z will be halved. (3) Y will be halved and Z will remain the same. (4) Y will remain the same and Z will be halved. 4. Which of the following graphs is correct for the photoelectric effect? (1) (2) (3) (4) 5. For which orbit in He+ ion, the circumference is 26.5 Å? (1) 2 (2) 3 (3) 4 (4) 16 6. The radius of the second orbit of H-atom is equal to the radius of (1) second orbit of He+ ion. (2) third orbit of Li2+ ion. (3) fourth orbit of He+ ion. (4) fourth orbit of Be3+ ion. 7. When an electron jumps from the second orbit to fourth orbit, its distance from nucleus increases by 2.116 Å. The atom or ion should be (1) H atom (2) He+ ion (3) Li2+ ion (4) Be3+ ion 8. The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is (ao is the Bohr radius) (1) 2 2 2 4 o h π ma (2) 2 2 2 16 o h π ma (3) 2 2 2 32 o h π ma (4) 2 2 2 64 o h π ma 9. The radius of first orbit of H-atoms is 0.529 Å. The radius of first orbit of D-atoms should be (1) exactly 0.529 Å. (2) slightly less than 0.529 Å. (3) slightly greater than 0.529 Å. (4) 1.058 Å One or more than one correct 10. The energy of an electron in the first Bohr's orbit of H-atom is –13.6 eV. The possible energy value(s) of the excited state(s) for electrons in Bohr's orbits to hydrogen is (1) –3.4 eV (2) –10.2 eV (3) –1.51 eV (4) −0.85 eV 11. As an electron jumps from the fourth orbit to the second orbit in Be3+ ion, its (1) kinetic energy increases. (2) speed increases. (3) frequency of revolution increases. (4) potential energy decreases. DPP - 1
2 12. Which of the following statement(s) is/are correct about the Bohr's model of hydrogen atom? (1) The acceleration of the electron in the n = 2 orbit is more than that in the n = 1 orbit. (2) The angular momentum of the electron in then n = 2 orbit is more than that in the n = 1 orbit. (3) The kinetic energy of electron in the n = 2 orbit is less than that in the n = 1 orbit. (4) The centripetal force of electron in the n = 2 orbit is more than that in the n = 1 orbit. Comprehension: 1 Three laser guns labelled as I, II and III have power 2, 3 and 5 W (not necessary in the same order) are used to produce photocurrent from metal plate. Number of photons emitted by laser guns are 4 × 1018, 5 × 1018 and 9 × 1018 per second. Metal plate have threshold energy 4.5 × 10−19 J. Neither the power nor the number of photons emitted by a particular laser gun is known and it is known that all capable photons emit a photoelectron. (NA = 6 × 1023, e = 1.6 × 10−19 C) 13. Minimum possible wavelength of emitted photoelectron is (1) 680Å (2) 30Å (3) 480Å (4) 120Å 14. Minimum photocurrent which must be passed through the circuit is (1) 2.88 A (2) 1.44 A (3) 2.08 A (4) 0.64 A 15. Ratio of maximum to minimum photocurrent which can be passed through the circuit is (1) 5 : 4 (2) 9 : 5 (3) 9 : 4 (4) 9 : 2 Comprehension: 2 A hydrogen-like atom (atomic number Z) is in a higher excited state of quantum number n. This excited atom an make a transition to the first excited state by successively emitting two photons of energies 10.20 and 17.00 eV, respectively. Alternatively, the atom from the same excited state can make a transition to the second excited state by successively emitting two photons of energies 4.25 and 5.95 eV, respectively 16. The value of ‘n’ is (1) 4 (2) 5 (3) 6 (4) 7 17. The value of Z is (1) 2 (2) 3 (3) 4 (4) 5 18. How much energy will be emitted when an electron in this atom moves from (n + 1) to ground state? (1) 114.75 eV (2) 117.5 eV (3) 119.9 eV (4) 122.74 eV Integer Type Questions – Single Digit (0–9) 19. The circumference of the second orbit of an atom or ion having single electron is 4 nm. The de Broglie wavelength of electron (in nm) revolving in this orbit is 20. The Schrodinger wave equation for hydrogen atom is Ψ2 s = 1 4√2π ( 1 a0 ) 3/2 (2 − r0 a0 ) e − r0 a0 , where a0 is Bohr's radius. If the radial node is 2s be at r0, then the value of r∘ ao is Matrix – Match Type Questions 21. Match the columns. Column I (Orbitals) Column II (Nodal properties) (A) 2s (P) Angular node = 1 (B) 1s (Q) Radial node = 0 (C) 2p (R) Radial node = 1 (D) 3p (S) Angular node = 0 (1) A → R, S; B → Q, S; C → P, Q; D → P, R (2) A → R, Q; B → R, S; C → R, P; D → P, S (3) A → R, Q; B → P, S; C → P, R; D → P, Q (4) A → R, S; B → Q, P; C → S, Q; D → P, Q 22. Match Column I with Column II in hydrogen atom spectrum. Column I Column II (A) Lyman series (P) Visible region (B) Balmer series (Q) Infrared region (C) Paschen series (R) Absorption spectrum (D) Brackett series (S) Ultraviolet region (1) A → R, S; B → P, S; C → Q; D → Q (2) A → R, Q; B → R, S; C → R, P; D → P, S (3) A → R, S; B → P, R; C → Q; D → S (4) A → R, S; B → Q, P; C → S, Q; D → P, Q
3 Answer Key 1 . ( 2 ) 2 . ( 3 ) 3 . ( 3 ) 4 . ( 2 ) 5 . ( 3 ) 6 . ( 4 ) 7 . ( 3 ) 8 . ( 3 ) 9 . ( 2 ) 10 . (1, 3, 4 ) 11 . (1, 2, 3, 4 ) 12 . (2, 3 ) 13 . ( 2 ) 14 . ( 4 ) 15 . ( 3 ) 16 . ( 3 ) 17 . ( 2 ) 18 . ( 3 ) 19 . ( 2 ) 20 . ( 2 ) 21 . ( 1 ) 22 . ( 1 )