Q1. An isotone of 76Ge32 is a) 77Ge32 c) 77Se34 b) 77As33 d) 79Se34 Q2. Thomson’s model was successful in explaining a) The H atomic spectrum c) The electrical neutrality of atom b) The circular motion of electrons d) Wave nature of electrons Q3. The number of electrons carrying a total charge of 1 C is – a) 6.023 X 1023 c) 6.25 X 1018 b) 6.25 X 1020 d) 6.023 X 1022 Q4. With an initial velocity V, an α particle can approach up to a distance r from a certain nucleus. If a proton is used instead of α particle to bombard the same nucleus, calculate the distance of closest approach with the same initial velocity. [Hint: take relative mass and charge !! ] a) r c) r/2 b) 2r d) r2 Q5. Which of the following atoms is expected to be most paramagnetic? a) 3Li c) 5B b) 4Be d) 6C Q6. The work function WA for a photoelectric metal A is 2 eV and WB for another metal B is 4 eV. If the photons of energy EA strike the surface of A, the ejected photoelectrons have a minimum De-Broglie wavelength λA and if photons of energy EB strike surface B, the DeBroglie wavelength of the ejected electrons is λB. If EB = EA + 0.5 in eV and if λB = 2λA, calculate the value of the stopping potential for metal A. a) 2 V c) 3 V b) 4 V d) 0.5 V Q7. The radial wave-function for an orbital is R = (1/45.96) X ρ 2 X Z3/2 X e-ρ/2 , where ρ = 2Zr/3. If the orbital angular momentum for an electron situated in this orbital is √6. (h/2π), identify the correct orbital. [Clue: number of radial nodes!!] a) 4p c) 4d b) 3d d) 3s Q8. Heisenberg’s uncertainty principle is applicable for a) a moving car c) a flying bird b) moving electrons d) all of these Q9. Kinetic energy and potential energy of electron in H atom at the 2nd excited state is a) 3.4 eV, - 6.8 eV c) 13.6 eV, -27.2 eV b) 10.2 eV, -20.4 eV d) 1.51 eV, -3.02 eV Q10. The work-function of a metal is 4 eV. The longest wavelength of light that can cause photoelectric emission from this metal is a) 400 nm c) 310 nm b) 124 nm d) 230 nm Q11. Which of the following sets of quantum numbers is wrong? a) n = 2, l = 2, m = 2, s = +1/2 c) n = 2, l = 0, m = 0, s = -1/2 b) n = 2, l = 1, m = 1, s = +1/2 d) n = 2, l = 0, m = 0, s = +1/2 Q12. Maximum number of electrons in a subshell with azimuthal quantum number l is a) 4l + 2 c) 2l + 1 b) 2l 2 d) l.(l+1) Q13. What is the longest wavelength line in the Lyman series of He+ ion? a) 3R c) 1/3R b) 1/4R d) ∞ Q14. The number of maxima in radial distribution curve of 5d orbital is a) 0 c) 1 b) 2 d) 3 Q15. In which of the following orbits of hydrogen atom, is the speed of electron maximum? a) n = 2 c) n = 4 b) n = 3 d) n = 1 Q16. The sub-shell that arises after f is called g. For an electron in any g orbital, which of the following is not the correct set of quantum numbers? a) n = 5, l = 4, m = -3, s = +1/2 c) n = 5, l = 3, m = -1, s = +1/2 b) n = 5, l = 4, m = +2, s = +1/2 d) n = 5, l = 4, m = +4, s = +1/2 Q17. For which system, is the Bohr model not applicable? a) C 5+ c) B4+ b) N 6+ d) Be2+ Q18. Total number of lines in Lyman series of hydrogen will be ( n = number of orbits present in atom) a) n c) n -1 b) n -2 d) {n (n + 1)}/2 Q19. Number of visible lines when an electron returns from 5th orbit to ground state for hydrogena) a)5 c) 4 b) 3 d) 10 Q20. The ratio of the energy of a photon of 200 nm wavelength radiation to that of 400 nm radiation is a) 1/4 c) 2 b) 1/2 d) 4 Q21. XY plane is nodal plane of which orbital? a) dxy c) py b) px d) pz Q22. The total electronic spin resulting from d7 configuration is – a) 1 c) 3/2 b) 5/2 d) 2 Q23. The mass of cathode ray is a) Same for different gases c) minimum for hydrogen b) Different for different gases d) maximum for hydrogen Q24. Which is not a property of a photon? a) Momentum c) energy b) Angular momentum d) wave-number Q25. A molecule absorbs a photon of wavelength λ and re-emits the same energy into two photons of wavelength λ1 and λ2 respectively. Find the correct relation a) λ = (λ1 + λ2)/ λ1. λ2 c) λ = λ1. λ2/ (λ1 + λ2) b) λ = (λ1 + λ2)2 / λ1. λ2 d) λ = λ1. λ2/ (λ1 + λ2)2 Q26. The De-Broglie wavelength (in Å) of an electron in 2nd orbit in hydrogen a) λ = 1.058π c) λ = 1.587π b) λ = 2.116π d) λ = π Q27. An oil drop has -6.4 X 10-19 C charge. Find the number of electrons in this oil drop. a) 2 c) 6 b) 4 d) 8 Q28. The approximate size of the nucleus 64Ni is a) 3 fm c) 5 fm b) 4 fm d) 2 fm Q29. The ratio of area enclosed by 2nd orbit of Be3+ and that by 1st orbit of He+ is a) 1:4 c) 1:8 b) 4:1 d) 8:1 Q30. Solving Schrödinger equation does not give information about the quantum number a) l c) s b) n d) m