Title 24. Atomic Physics - Medium-2.pdf ✅

1. Which of the following particle has similar mass to electron ? (a) Proton (b) Neutron (c) positron (d) Neutrino 2. Different atoms of same element which have different mass but have same chemical properties are called: (a) isochoric (b) isotope (c) isobar (d) isobaric 3. The mass numbers of nuclei A and B are respectively 135 and 5. The ratio of their radii (a) 1 : 3 (b) 3 : 1 (c) 27 : 1 (d) 1: 27 4. If the nucleus 27 13 AI has a nuclear radius of about 3.6 fm, then 125 52 Te would have its radius approximately as : (a) 6.0 fm (b) 9.6 fm (c) 12.0 fm (d) 4.8 fm 5. Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be (a) 1 : 3 (b) 3 : 1 (c) (c)1/3 : 1 (d) 1 : 1 6. A nucleus disintegrates into two nuclear parts which have their velocities in the ratio 2 : 1. The ratio of their nuclear sizes will be : (a) 2 1/3 : 1 (b) 1 : 31/2 (c) 3 1/2 : 1 (d) 1 : 21/3 7. The uncle of which one of the following pairs of nuclei are isotones :- (a) 34Se74 , 31Ga71 (b) 38Sr84 , 38sr86 (c) 42Mo92 , 40Zr92 (d) 20Ca40 , 16S 32 8. The order of magnitude of density of uranium nucleus is, (mp = 1.67 × 10–27 kg) : (a) 1020 kg m–3 (b) 1017 kg m–3 (c) 1014 kg m–3 (d) 1011 kg m–3 9. The mass number of a nucleus is (a) always less than its atomic number (b) always more than its atomic number (c) sometimes equal to its atomic number (d) sometimes less than and sometimes more than its atomic number 10. Masses of nucleus, neutron and protons are M, n m and mp respectively. If nucleus has been divided in to neutrons and protons, then (a) M = (A – Z) mn + Zmp (b) M = Zmn + (A – Z) mp (c) M < (A – Z) mn + Zmp (d) M > (A – Z)mn + Zmp 11. As the mass number A increases, the binding energy per nucleon in a nucleus (a) increases (b) decreases (c) remains the same (d) varies in a way that depends on the actual value of A. 12. Which of the following is a wrong description of binding energy of a nucleus ? (a) It is the energy required to break a nucleus into its constituent nucleons. (b) It is the energy released when free nucleons combine to from a nucleus (c) It is the sum of the rest mass energies of its nucleons minus the rest mass energy of the nucleus (d) It is the sum of the kinetic energy of all the nucleons in the nucleus 13. The energy of the reaction Li7 + p ⎯→ 2 He4 is (the binding energy per nucleon in Li7 and He4 nuclei are 5.60 and 7.06 MeV respectively.) (a) 17.3 MeV (b) 1.73 MeV (c) 1.46 MeV (d) depends on binding energy of proton 14. The binding energies of two nuclei Pn and Q2n and x and y joules. If 2x > y then the energy released in the reaction P n + Pn → Q 2n, will be (a) 2x + y (b) 2x – y
(c) –(2x – y) (d) x + y 15. 1H1 + 1H1 + 1H2 → X + 1 e 0 + energy .The emitted particle is - (a) Neutron (b) Proton (c) -particle (d) Neutrino 16. The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit). The binding energy of 4 2He is (Given:- helium nucleus mass  4.0015 u) (a) 0.0305 J (b) 0.0305 erg (c) 28.4 MeV (d) 0.061 U 17. For the stability of any nucleus (a) binding energy per nucleon will be more (b) binding energy per nucleon will be less (c) number of electrons will be more (d) none of the above 18. IF Mo is the mass of an oxygen isotope 8O17, Mp asd Mn are the masses of a proton and a neutron, respectively the nuclear binding energy of the istope is (a) (M0 – 8Mp ) C2 (b) ( Mo – 8MP – 9Mn ) C2 (c) Moc2 (d) (Mo – 17 Mn) C2 19. Mp denotes the mass of a proton and Mn that of a neutron. A given nucleus, of binding energy B, contains Z protons and N neutrons. The mass M (N,Z) of the nucleus is given (c is velocity of light) (a) M(N, Z) = NMn + ZMp + B/c2 (b) M(N, Z) = NMn + ZMp – B/c2 (c) M(N, Z) = NMn – ZMp + B/c2 (d) M(N, Z) = NMn – ZMp – B/c2 20. In the reaction 2 1 H + 3 1 H → 4 2 HE + 1 0 n. If the binding energies of 2 1 H, 3 1 H and 4 2 He are respectively a, b and c (in MEV), then the energy (in MeV eleased in this reaction is ) (a) a + b + c (b) c + a + b (c) c – (a + b) (d) a + b + c 21. The binding energy of deuteron is 2.2 MeV and that of 4 2 He is 28 MeV. If two deuterons are fused to form one 4 2 He then the energy released is :- (a) 25.8 MeV (b) 23.6 MeV (c) 19.2 MeV (d) 30.2 MeV 22. If the binding energy per nucleon in 7 3 Li and 4 2He nuclei are 5.60 MeV and 7.06 MeV respectively, then in the reaction 7 4 p Li 2 He + → 3 2 energy of proton must be : (a) 39.2 MeV (b) 28.24 MeV (c) 17.28 MeV (d) 1.46 MeV 23. If Mo is the mass of an oxygen isotope 8O17, Mp and MN are the masses of a proton and a neutron respectively, the nuclear binding energy of the isotope is : (a) (Mo – 8MP )C2 (b) (Mo – 8MP – 9MN )C2 (c) MoC2 (d) (Mo – 17MN )C2 24. Binding energy per nucleon is of the order of - (a) 7.6 eV (b) 7.6 eV (c) 7.6 MeV (d) 7.6 KeV 25. A free neutron decays to a proton but a free proton does not decay to a neutron. This is beacuse (a) neutron is a composite particle made of a proton and an electron whereas proton is fundamental particle (b) neutron is an uncharged particle whereas proton is a charged particle (c) neutron has larger rest mass than the proton (d) weak forces can operate in a neutron but not in a proton. 26. MP and MN are masses of proton and neutron, respectively, at rest. If they combine to form deuterium nucleus. The mass of the nucleus will be : (a) less than MP (b) less than (MP + MN ) (c) less than (MP + 2MN ) (d) greater than (MP + 2MN )
27. The figure shows a plot of binding energy per nucleon (B.E/A) vs mass number (A) for nuclei. Four nuclei, P, Q, R and S are indicated on the curve. The process that would release energy is (a) R → 2S (b) P → Q + S (c) P → 2R (d) Q → R + S 28. A positron of 1MeV collides with an electron of 1 MeV and gets annihilated and the reaction produces two -ray photons. If the effective mass of each photon is 0.0016 amu, then the energy of each -ray photon is about- (a) 1.5 MeV (b) 3 MeV (c) 6 MeV (d) 2 MeV 29. Mn and Mp represent the mass of neutron and proton respectively An element having mass M has N neutron and Z- protons, then the correct relation will be :- (a) M < {N.mn + Z.Mp } (b) M > {N.mn + Z.Mp } (c) M = {N.mn + Z.Mp } (d) M = N {.mn + Mp } 30. 1 amu is equivalent to : (a) 931 MeV (b) 0.51eV (c) 9.31 MeV (d) 1.02 MeV 31. Mass-energy equation E = mc2 was given by (a) Newton (b) Kepler (c) Einstein (d) Millikan 32. A nucleus A z X has mass represented by M(A, Z). If Mp and Mn denote the mass of proton and neutron respectively and BE the binding energy (in MeV), then : (a) BE = [M(A,Z) – ZMp –(A – Z) Mn ]c2 (b) BE = [ZMp +(A – Z) Mn – M (A, Z) ]c2 (c) BE = [ZMp +AMn – M (A,Z)]c2 (d) BE = M (A,Z) – ZMp –(A – Z) Mn 33. Complete the equation for the following fission process : 92U 235 + on 1 ⎯⎯→ 38Sr 90 + ....... (a) 54Xe143 + 3 0 n 1 (b) 54Xe145 (c) 57Xe142 (d) 54Xe142 + 0 n 1 34. The above is a plot of binding energy per nucleon Eb , against the nuclear mass M; A, B, C, D, E, correspond to different nuclei. Consider four reactions : (i) A + B → C +  (ii) C → A + B +  (iii) D + E → F +  and (iv) F → D + E + , where  is the energy released. In which reactions  positive? (a) (i) and (iii) (b) (ii) and (iv) (c) (ii) and (iii) (d) (i) and (iv) 35. An -particle is bombarded on 14N. As a result, a 17O nucleus is formed and a particle is emitted. This particle is a (a) neutron (b) proton (c) electron (d) positron 36. A free neutron decays into a proton, an electron and : (a) A neutrino (b) An antineutrino (c) An -particle (d) A -particle 37. When a  − -particle is emitted from a nucleus, the neutron- proton ratio : (a) is decreased (b) is increased (c) remains the same (d) first (a) then (b) 38. In one  and 2 -emissions : (a) mass number reduces by 2
(b) mass number reduces by 6 (c) atomic number reduces by 2 (d) atomic number remains unchanged 39. Which ray contain (+Ve) charge particle :- (a) -rays (b) -rays (c) -rays (d) X-rays 40. Which of the following cannot be bombarded to disintegrate a nucleus - (a) -ray (b) -ray (c) -ray (d) laser 41. Which of the followings is a correct statement? (a) beta rays are same as cathode rays. (b) gamma rays are high energy neutrons. (c) alpha particles are singly-ionized helium atoms. (d) protons and neutrons have exactly the same mass. 42. A deutron is bombared on 8O16 nucleus then -particle is emitted then product nucleus is :- (a) 7N13 (b) 5B10 (c) 4Be9 (d) 7N14 43. An  – particle is bombarded on N14 As. a result, a O17 -nucleus is formed and a particle X is emitted. The particle X is (a) neutron (b) proton (c) electron (d) positron 44. In the reaction 92X234 ⎯⎯→ 87 Y 222 How many -particles and -particles are emitted? (a) 3 and 5 (b) 5 and 3 (c) 3 and 3 (d) 3 and 1 45. Which of the following radiations has the least wavelength? (a) -rays (b) -rays (c) -rays (d) X-rays 46. When U238 nucleus originally at rest, decays by emitting an alpha particle having a speed u, the recoil speed of the residual nucleus is : (a) 4u 238 (b) – 4u 234 (c) 4u 234 (d) – 4u 238 47. A nucleus with Z = 92 emits the following in a sequence : , ,  – ,  – , , , , ;  – ,  – , ,  + ,  + , . The Z of the resulting nucleus is : (a) 76 (b) 78 (c) 82 (d) 74 48. A nuclear reaction given by zXA → z+1YA + –1 e 0 +  represents (a) -decay (b) -decay (c) fusion (d) fission 49. in radioactive decay process the negatively charged emitted  – particles are (a) the electrons present inside the nucleus (b) the electrons produced inside as a result of the decay of nautrons inside the nucleus (c) the electrons produced as a result of collisions between atoms (d) the electrons orbiting around the nucleus 50. Ub the disintegration series 92 238 U ⎯⎯→ X – ⎯⎯⎯→ Y z A the values of Z and A respectively will be (a) 92, 236 (b) 88, 230 (c) 90, 234 (d) 91, 234 51. A nucleus represented by thesymbol A z X has :- (a) Z protons and A – Z neutrons (b) Z protons and A neutrons (c) A protons and Z – A neutrons (d) Z protons and A – Z PROTONS 52. A nuclear transformation is denoted by X(n, ) → 7 3 Li . Which of the following is the nucleus of element X? (a) 12 6 C (b) 10 5 B (c) 9 5B (d) 11 4Be