Tiêu đề 13. NUCLEI.pdf ✅

compained by neutrino (b) Nuclear force is charge independent (c) fusion is the chief source of stellar energy (1) (a), (b) are correct (2) (a), (c) are correct (3) only (a) is correct (4) (b), (c) are correct 11. Read the Assertion and Reason carefully to mark the correct options given below: Assertion : In both radioactivity and photoelectric effect, electrons may be rejected. Reason : In photoelectric effect and radioactivity emission occurs only of unstable elements. (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) Assertion is incor- rect but reason is correct. 12. In nuclear reaction, denotes (1) electron (2) positron (3) proton (4) neutron 13. The energy equivalent of of substance is (1) (2) (3) (4) 14. If total energy of electron is then its rest mass energy is (1) (2) (3) (4) 15. Sun radiates energy at the rate of . The rate of decrease in mass of sun is . (1) (2) (3) (4) 16. What is the power output of reactor if it takes 30 days to use up of fuel and if each fis‐ sion gives of usable energy? Avogadro’ number (1) (2) (3) (4) 17. Nucleus of an atom whose atomic mass is 24 consists of (1) 11 electrons, 13 protons and 11 neutrons (2) 11 electrons, 11 protons and 13 neutrons (3) 11 protons, 13 electrons (4) 11 protons, 13 neutrons 18. The binding energies of the atoms of elements and are and , respectively. Three atoms of the element fuse to give one atom of element . This fusion process is accompanied by release of energy . Then, and are related to each other as (1) (2) (3) (4) 19. A radioactive sample undergoes decay as per the following graph. At time , the number of undecayed nuclei is Calculate the number of nuclei left after . (1) (2) (3) (4) 20. The fraction of radioactive material that has decayed in time , varies with time . The correct variation is given by the curve (1) (2) (3) (4) 21. Following process is known as (1) pair production (2) photoelectric effect (3) Compton effect (4) Zeeman effect 22. Assertion : There is a chain reaction when uranium is bom‐ barded with slow neutrons. Reason : 2He 4+ZXA→Z+2Y A+3+ZMA M 1g 5.6 eV 5.6 × 10 12 MeV 11.2 × 10 24 MeV 5.6 × 10 26 MeV 3.555 MeV 3.555 MeV 3.045 MeV 0.00055 MeV 0.511 MeV 3.6 × 10 26 J/s (kgs −1) 12 × 10 10 1.3 × 10 20 4 × 10 9 3.6 × 10 36 92U 235 2g 185 MeV = 6.02 × 10 26mol −1 45 MW 58.46 MW 72 MW 92 MW A B Ea Eb B A e Ea, Eb e Ea + e = 3Eb Ea = 3Eb Ea − e = 3Eb Ea + 3Eb + e = 0 t = 0 No . 1 h No/e 8 No/e 10 No/e 12 No/e 14 f t t A B C D hν ⟶ e + + e −
When uranium is bombarded with slow neutrons more neutrons are produced. (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) Assertion is incor- rect but reason is correct. 23. Which of the following are correct? I. Nuclear density is costant for all matter. II. Nuclear density is around III. Mass of ordinary matter is mainly due to nucleus. (1) I, II and III (2) II and III (3) I and II (4) Only I 24. has 92 protons and 238 nucleons. If de‐ cays by emitting an alpha particle and becomes (1) (2) (3) (4) 25. A radioactive nucleus of mass emits a pho‐ ton of frequency and the nucleus recoils. The recoil energy will be (1) (2) (3) (4) 26. The half-life of a radioactive isotope is 50 yr. It decays to another element Y which is stable. The two elements and were found to be in the ratio of 1:15 in a sample of a given rock. The age of the rock was estimated to be (1) (2) (3) (4) 27. The binding energy per nucleon is maximum in the case of (1) (2) (3) (4) 28. The end product of decay is . The number of and particles emitted are respectively (1) (2) (3) (4) 29. The particle is converted to via following reactions then (1) and are isobars (2) and are isotopes (3) and are isobars (4) and are isotopes 30. The above is a plot of binding energy per nu‐ cleon against the nuclear mass correspond to different nuclei. Consider four reactions Where is the energy released? In which reac‐ tions is positive? (1) (i) and (iv) (2) (i) and (iii) (3) (ii) and (iv) (4) (ii) and (iii) 31. Assertion : Generally heavy nuclei are unstable. Reason : Heavy nucleus has more neutrons and protons. (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) Assertion is incor- rect but reason is correct. 32. The fraction of the initial number of radioactive nuclei which remain undecayed after half of a half - life of the radioactive sample is (1) (2) (3) (4) 33. The mother and daughter elements, with emis‐ sion of -rays are (1) Isotopes (2) Isobars (3) Isomers (4) Isodiapheres 34. The binding energy per nucleon of dueterium and helium nuclei are and re‐ spectively. When two deuterium nuclei fuse to form a helium nucleus the energy released in the fusion is: 2.3 × 10 17kg/m3 238U 234 92 U 234 90 Th 235 92 U 237 93 Np M v h 2v 2/2Mc 2 Zero hv Mc 2 − hv X X Y 250 yr 100 yr 200 yr 150 yr 56 26Fe 4 2He 235 92 U 141 56 Ba 90Th 232 82Pb 208 α β 6, 0 3, 3 4, 6 6, 4 A C A → B + 2He 4 B → C + 2−1e 0 A C A C A B A B Eb, M; A, B, C, D, E & F (i)A + B → C + ε (ii)C → A + B + ε (iii)D + E → F + ε (iv)F → D + E + ε ε ε 1 4 1 2√2 1 2 1 √2 γ 1.1 MeV 7 MeV
(1) (2) (3) (4) 35. If is the mass of an oxygen isotope are the masses of a proton and a neutron respectively the nuclear binding energy of the isotope is: (1) (2) (3) (4) 36. Assertion : In -decay, atomic number of daughter nucleus reduces by a unit from the parents nucleus. Reason : An -particle carries four units of mass. (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) Assertion is incor- rect but reason is correct. 37. In the given nuclear reaction, the element is (1) (2) (3) (4) 38. Assertion : Out of the following, viz electron, neutron, and proton, which is not emitted in radioactive emission is . Reason : Only charged particles can be emitted in radio activity. (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) Assertion is incor- rect but reason is correct. 39. Two protons are kept at a separation of 10 . Let and be the nuclear force and the elec‐ tromagnetic force between them (1) (2) and differ only slightly (3) (4) 40. A certain mass of hydrogen is changed to he‐ lium by the process of fusion. The mass defect in fusion reaction is 0.02866 . The energy liber‐ ated per is (given ) (1) (2) (3) (4) 41. If of energy is released in the fission of 1 nucleus of , then the number of nuclei that undergo fission to produce energy of in , is: (1) (2) (3) (4) 42. Energy released in the fission of a single nucleus is . The fission rate of fueled reactor operating at a power level of is: (1) (2) (3) (4) 43. The binding energies of the nuclei and are and respectively. Three nuclei of the ele‐ ment fuse to give one nucleus of element ' ' and an energy ' ' is released. Then , are related (1) (2) (3) (4) 44. Assertion : Cobalt-60 is useful in cancer therapy. Reason : Cobalt-60 is source of -radiations capable of killing cancerous cell. (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. 45. What is the -value of the reaction The atomic masses of and are and respectively (1) (2) (3) (4) 24.6 MeV 25.1 MeV 22.3 MeV 23.6 MeV M0 8O17 , mp and mn (M0 − 8mp)c 2 (9mn + 8mp − M0)c 2 M0c 2 (M0 − 17mn)c 2 α α X 22 11Na → X + e + + v 23 10Ne 22 10Ne 22 12Mg 23 11Na 4 2He n nm Fn Fe Fe << Fn Fe Fn Fe = Fn Fe >> Fn u u 1u = 931 MeV 2.67 MeV 26.7 MeV 6.675 MeV 13.35 MeV 200 MeV 92U 235 10 kWh 1s 11.25 × 10 18 22.5 × 10 17 11.25 × 10 17 22.5 × 10 18 92U 235 200 MeV 92U 235 5 W 1.56 × 10 10s−1 1.56 × 10 11 s−1 1.56 × 10 16s −1 1.56 × 10 17s −1 A B Ea Eb B A Q Ea, Eb Q Ea − 3Eb = Q Eb − 3Ea = Q Ea + 3Eb = Q Eb + 3Ea = Q γ Q p + 7Li → 4He + 4He 1H, 4He 7Li 1.007825 u, 4.002603 u 7.016004 u 17.35 MeV 18.06 MeV 177.35 MeV 170.35 MeV