Title MODERN PHYSICS II.pdf ✅

Modern Physics  Digital www.allendigital.in [ 231 ] NUCLEAR PHYSICS 1. Let Fpp, Fpn and Fnn denote the nuclear force between proton–proton, proton–neutron and neutron–neutron pair respectively. When separation is 1 fm :- (1) Fpp < Fpn = Fnn (2) Fpp > Fpn = Fnn (3) Fpp = Fpn = Fnn (4) Fpp < Fpn < Fnn 2. A nuclear fission is given below A240 → B100 + C140 + Q(energy) Let binding energy per nucleon of nucleus A, B and C is 7.6 MeV, 8.1 MeV and 8.1 MeV respectively. Value of Q is :-(Approximately) (1) 20 MeV (2) 220 MeV (3) 120 MeV (4) 240 MeV 3. How much energy will be released when 10 kg of U235 is completely converts into energy :- (1) 5 × 1027 MeV (2) 5 × 1024 MeV (3) 9 × 1017 J (4) All of these 4. How much energy is released when 2 mole of U235 is fissioned :- (1) 1024 MeV (2) 24 × 1025 MeV (3) 1024 J (4) 1024 kWh 5. As the mass number increases, binding energy per nucleon :- (1) increases (2) decreases (3) remains same (4) may increase or may decrease 6. Possible forces on a proton by a proton in a nucleus is/are :- (1) Coulomb force (2) Nuclear force (3) Gravitational force (4) All of these 7. The energy radiated by a red giant star produces by :- (1) Fission process (2) Fusion process (3) Chemical burning of hydrogen (4) Gravitational contraction 8. In the process of atomic explosion, the most of fission energy is released in the form of :– (1)  - rays (2) Kinetic energy of products (3) Infra red rays (4) Visible light 9. Which of the following nucleus is fissionable by slow neutrons :- (1) 92U238 (2) 93Np239 (3) 92U235 (4) 2He4 10. The example of nuclear fusion is . (1) formation of barium and krypton from uranium (2) formation of helium from hydrogen (3) formation of plutonium –235 from uranium –235 (4) formation of water from hydrogen and oxygen 11. Electron - positron pair can be created by -rays. In this process the minimum energy of -rays should be :- (1) 5.0 MeV (2) 4.02 MeV (3) 15.0 MeV (4) 1.02 MeV 12. For nuclear reaction : 92U235 + 0n1 → 56Ba144 + ..........+3 0n1 (1) 26Kr89 (2) 36Kr89 (3) 26Sr90 (4) 38Sr89 13. For the given reaction, the particle X is - 6C11 → 5B11 + + + X (1) Neutron (2) Anti neutrino (3) Neutrino (4) Proton 14. In a breeder reactor, useful fuel obtained from U238 is : (1) Ac233 (2) Th238 (3) U235 (4) Pu239 15. Boron used in Atomic Reactor for:- (1) absorbption of neutrons (2) absorbption of  - particles (3) speed up the reaction (4) change the reaction 16. Who discovered the nuclear fission :- (1) Otto Hahn and strassman (2) Fermi (3) Baithe (4) Rutherford 17. Which one is best neutron moderator in all respects: (1) Barium oxide (2) Water (3) Graphite (4) Heavy water Exercise - I
NEET : Physics [ 232 ] www.allendigital.in  Digital 18. X(n, ) 7 3 Li , then the element X will be :– (1) 10 5 B (2) 9 5B (3) 11 4 Be (4) 4 2He 19. Mn and Mp represent the mass of neutron and proton respectively. An element having nuclear mass M has N neutrons and Z-protons, then the correct relation will be :- (1) M<{N.Mn+Z.Mp} (2) M>{N.Mn+Z.Mp } (3) M={N.Mn+Z.Mp} (4) M=N{Mn + Mp} 20. Energy is released in nuclear fission is due to (a) Few mass is converted into energy (b) Total binding energy of fragments is more than the B.E. of parental element (c) Total B.E. of fragments is less than the B.E. of parental element (d) Total B.E. of fragments is equals to the B.E. of parental element is (1) a,c (2) a,b (3) a,d (4) All 21. Energy in an atom bomb is produced by the process of : (1) nuclear fusion (2) nuclear fission (3) combination of hydrogen atoms (4) combination of electrons and protons 22. Assuming that 200 MeV of energy is released per fission of 92U235 atom. Find the number of fission per second required to release 1 kW power :- (1) 3.125 × 1013 (2) 3.125 × 1014` (3) 3.125 × 1015 (4) 3.125 × 1016 23. 1 a.m.u. (1.66 × 10–27 kg) is equal to (1) 139 MeV/c2 (2) 39 MeV/c2 (3) 93 MeV/c2 (4) 931 MeV/c2 24. In nuclear fission the percentage of mass converted into energy is about :- (1) 0.1% (2) 1% (3) 10% (4) 0.01% 25. Which of the following are suitable for the fusion process :- (1) Light nuclei (2) heavy nuclei (3) Element must be lying in the middle of the periodic table (4) Middle elements, which are lying on binding energy curve 26. Which one of the following particle is unstable? (1) -particle (2) electron (3) proton (4) neutron 27. Which of the following is weakest force :- (1) Gravitational force (2) Electric force (3) Magnetic force (4) Nuclear force 28. The volume occupied by an atom is greater than the volume of the nucleus by a factor of about :- (1) 101 (2) 105 (3) 1010 (4) 1015 29. The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit). The binding energy of 2 4He is :- (1) 0.0305 J (2) 0.0305 erg (3) 28.4 MeV (4) 0.061 u (Given:- mass of helium nucleus 4.0015 u) 30. The mass number of a nucleus is (1) always less than its atomic number (2) always more than its atomic number (3) may equal to its atomic number (4) sometimes less than and sometimes more than its atomic number 31. In the following reaction X is :– 20Ca40 + X → 21Sc43 + 1H1 (1) Electron (2) Positron (3) alpha particle (4) Proton 32. Nuclear fusion is possible :– (1) only between light nuclei. (2) only between heavy nuclei. (3) between both light and heavy nuclei. (4) only between nuclei which are stable against –decay. 33. The order of nuclear density is (1) 1013 kg/m3 (2) 1015 kg/m3 (3) 1017 kg/m3 (4) 1019 kg/m3 34. Two light nuclei of masses m1 and m2 are fused to form a more stable nucleus of mass m3 then:- (1) m3 = m m 1 2 − (2) m3 < (m1 + m2) (3) m3 > (m1 + m2) (4) m3 = m1 + m2 35. A nucleus represented by the symbol A Z X has :- (1) Z protons and A – Z neutrons (2) Z protons and A neutrons (3) A protons and Z – A neutrons (4) Z neutrons and A – Z protons

NEET : Physics [ 234 ] www.allendigital.in  Digital 50. Which spectrum is continuous (1) –rays (2) –rays (3) –rays (4) All of these 51. Which statement about radioactive radiations is true (1) Speed of -particles is a characteristic property. (2) Speed of -particles is a characteristic property. (3) Speed of -photon is a characteristic property. (4) All of these. 52. Which one moves with greatest speed :- (1) -rays (2) –rays (3) –rays (4) cathode rays 53. For a radioactive sample, at given instant, number of active nuclei is N and its decay constant is  then the incorrect relation is– (1) N = activity at given instant. (2)  = decay probability per unit time for a nucleus (3) After the next 1  time interval, active nuclei in the sample will be N 1 1 e   −     (4) The half life of the sample = n2  54. If a nucleus is emitting e– particle, its neutron to proton ratio (n/p) will :– (1) Increase. (2) Decrease (3) Remain unchanged (4) Can't be determined. 55. A radioactive source is kept in an uniform electric field ,  and - particle are emitting.  are respectively :- (1) A,B,C (2) A,C,B (3) C,A,B (4) C,B,A 56. The rate of disintegration of a radioactive sample can be increased by :- (1) Increasing the temperature (2) Increasing the pressure (3) Chemical reaction (4) It is not possible 57. In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following would be emitted in the decay process. (1) Proton (2) Neutron (3) Electron (4) Photon 58. At some instant two radioactive substance are having amount in ratio of 2 : 1. Their half lives are 12 hrs and 16 hrs then after two days the ratio of their quantities is (1) 1 : 1 (2) 2 : 1 (3) 1 : 2 (4) 1 : 4 59. The isotope used for curing the cancer is : (1) K (40) (2) Co (60) (3) Sr (90) (4) I (131) 60. 'Rn' decays into 'Po' by emitting -particle with half life of 4 days. A sample contains 6.4 × 1010 atoms of Rn. After 12 days, the number of atoms of 'Rn' left in the sample will be- (1) 3.2 × 1010 (2) 0.53 × 1010 (3) 2.1 × 1010 (4) 0.8 × 1010 61. Neutrino is a particle, which is : (1) charged like an electron and has no spin (2) chargeless and has spin (3) chargeless and has no spin (4) charged like an electron and has spin 62. A radioactive element 238 90X decays in to 222 83Y . The number of  - particles emitted is: (1) 2 (2) 4 (3) 6 (4) 1 63. The relation between  and T1/2 as :- (T1/2 → half life,  → decay constant) (1) T1/2 =  n2 (2) T1/2 n2 =  (3) T1/2 = 1  (4) ( + T1/2) = 2 n2 64. The half life of a radioactive material is 5 years. The probability of disintegration for a nucleus in 10 years is :- (1) 0.50 (2) 0.25 (3) 0.60 (4) 0.75 65. 10.24 g radioactive substance has half life 3.8 days. After 19 days, its remaining quantity is :- (1) 0.151 g (2) 0.32 g (3) 1.51 g (4) 0.16 g + A C B + + + + + + +