Tiêu đề 13.NUCLEI - Questions.pdf ✅

13.NUCLEI (1.)1 g of hydrogen is converted into 0.993 g of helium in a thermonuclear reaction. The energy released is (a.) 63 × 107 J (b.) 63 × 1010J (c.) 63 × 1014J (d.) 63 × 1020J (2.)If the binding energy per nucleon in 3Li 7 and 2He 4nuclei are respectively 5.60 MeV and 7.06 MeV, then the energy of proton in the reaction 3Li + p → 22He 4 is (a.) 19.6 MeV (b. ) 2.4 MeV (c.) 8.4 MeV (d. ) 17.3 MeV (3.)The energy released in the fission of 1Kg of 92U 235 is (energy per fission =200 MeV) (a.) 5.1 × 1026eV (b. ) 5.1 × 1026 J (c.) 8.2 × 1013 J (d. ) 8.2 × 1013 MeV (4.)An electron jumps from the 4 th orbit to the 2 nd orbit of hydrogen atom. Given the Rydberg’s constant R = 105 cm−1 . The frequency in Hz of the emitted radiation will be (a.) 3 16 × 105 (b.) 3 16 × 1015 (c.) 9 16 × 1015 (d.) 3 4 × 1015 (5.)The half-life of radioactive Polonium (Po) is 138.6 days. For ten lakh Polonium atoms, the number of disintegration in 24 hours is (a.) 2000 (b.) 3000 (c.) 4000 (d.) 5000 (6.)The fact that photons carry energy was established by (a.) Doppler’s effect (b.) Compton’s effect (c.) Bohr’s theory (d.) Diffraction of light (7.)Half-life of radioactive substance is 3.20 h. What is the time taken for a 75% of substance to be used? (a.) 6.38 h (b.) 12 h (c.) 4.18 day (d.) 1.2 day (8.)The half-life of a radioactive element is 3.8 days. The fraction left after 19 days will be (a.) 0.124 (b.) 0.062 (c.) 0.093 (d.) 0.031 (9.)The count rate of a Geiger-Muller counter for the radiation of a radioactive material of half life of 30 minutes decreases to 5 s −1 after 2 hours. The initial count rate was (a.) 25 s −1 (b.) 80 s −1 (c.) 625 s −1 (d.) 20 s −1 (10.)If 92U 238 undergoes successively 8 α-decays and 6 β-decays, then resulting nucleus is (a.) 82U 206 (b.) 82Pb206 (c.) 82U 210 (d.) 82U 214 (11.)Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is (a.) 54.4 eV (b.) 13.6 eV (c.) 40.8 eV (d.) 27.2 eV (12.)A radioactive element 90X 238 decays into 83Y 222. The number of β −particles emitted are (a.) 4 (b.) 6 (c.) 2 (d.) 1 (13.)1 atomic mass unit is equal to (a.) 1 25 (mass of F2 molecule) (b.) 1 14 (mass of N2 molecule) (c.) 1 12 (mass of one C-atom) (d.) 1 16 (mass of O2 molecule) (14.)U 238 decays into Th 234 by the emission of an α −particle. There follows a chain of further radioactive decays, either by α −decay or by β −decay. Eventually a stable nuclide is reached and after that, no further radioactive decay is possible. Which of the following stable nuclides is the end product of the U 238 radioactive decay chain