Nuclei — practice questions
114 curated practice questions from Nuclei (Physics Class 12, CBSE) — 90 easy, 23 medium, 1 hard. Every question includes the final answer free; step-by-step worked solutions with a free account.
- Two radioactive substances A and B have decay constants 5λ and λ respectively. At t = 0, they have the same number of…
- Two spherical nuclei have mass numbers 216 and 64 with their radii R 1 and R 2 respectively. The ratio, R_1 R_2 is…
- Which of the following statements is not true for nuclear forces?
- Inside a nucleus, the nuclear forces between proton and proton, proton and neutron, neutron and neutron are F_ p p , F_…
- Which of the following is an essential requirement for initiating the fusion reaction?
- A 280 day old radioactive substance shows an activity of 6000 dps 140 days later its activity becomes 3000 dps. What…
- In Rutherford's nuclear model of the atom, the entire positive charge and most of the mass of the atom are concentrated…
- In Rutherford's nuclear model of the atom, the entire positive charge and most of the mass of the atom are concentrated…
- The potential energy of a pair of nucleons is minimum when they are separated by about:
- If the nuclear force between two protons, two neutrons and between proton and neutron is denoted by F pp , F nn and F…
- Which of the following has the highest neutron ratio? _ 8 O ^ 16 2 He 4 _ 26 Fe ^ 56 92 U 235
- In a nuclear fusion reaction, two nuclei, A and B fuse to produce a nucleus C, releasing an amount of energy E in the…
- The ratio of the nuclear radii of the gold isotope and silver isotope is
- The decay constant, for a given radioactive sample, is 0.3465 day –1 . What percentage of this sample will get decayed…
- An element A decays into an element C by a two step process A → B + 2 He 4 and B → C + 2 e – . Then,
- Two nuclei have their mass numbers in the ratio of 1 : 27. What is the ratio of their nuclear densities?
- A sample of a radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the…
- What amount of energy is released by deuterium and tritium fusion?
- M x and M y denote the atomic masses of the parent and the daughter atom respectively in a radioactive decay. The Q…
- The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it…
- The potential energy between two nucleons inside a nucleus is minimum at a distance of about
- The binding energy per nucleon of deuterium and helium nuclei are 1.1 MeV and 7.0 MeV respectively. When two deuterium…
- The mass number of iron nucleus is 55.854 and A = 56, the nuclear density is
- The radius of germanium (Ge) nuclide is measured to be twice the radius of _ 4 ^ 9 Be . The number of nucleons in Ge are
- Assertion (A): Forces acting between proton-proton (f pp ) proton-neutron (f pn ) and neutron-neutron (f nn ) are such…
- Tritium with a half-life of 12.5 years undergoing beta decay. What fraction of a sample of pure tritium will remain…
- Two nuclei have their mass numbers in the ratio of 8 : 1. The ratio of their nuclear densities is:
- Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be
- Assertion (A): During formation of a nucleus, the mass defect produced is the source of the binding energy of the…
- The fission properties of 23 9 9 4 Pu are very similar to those of 23 5 9 2 U. The average energy released per fission…
- Rutherford’s experiments suggested that the size of the nucleus is about
- Complete the equation for the following fission process _ 92 U ^ 235 + _ 0 n^ 1 _ 38 Sr ^ 90 +
- For a nuclear fusion process, the suitable nuclei are:
- Carbon dating is best suited for determining the age of fossils, if their age in years is of the order of
- Radioactive Co is transformed into stable Ni by emitting two g -rays of energies
- The decay constant of a radio active isotope is λ. If A 1 and A 2 are its activities at times t 1 and t 2 respectively…
- The mass of -particle is less than the sum of masses of two protons and two neutrons. equal to mass of four protons…
- M n and M p represent the mass of neutron and proton respectively. An element having mass M has N neutrons and Z…
- A radioactive nucleus of mass M emits a photon of frequency u and the nucleus recoils. The recoil energy will be
- If in a nuclear fusion reaction, mass defect is 0.3%, then energy released in fusion of 1 kg mass
- O 2 molecule consists of two oxygen atoms. In the molecule, nuclear force between the nuclei of the two atoms
- Fusion reaction takes place at high temperature because
- Let m p be the mass of a proton, m n the mass of a neutron, M 1 the mass of Ne nucleus and M 2 the mass of Ca nucleus…
- Two stable isotopes and have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600…
- In the nucleus of 11 Na 23 , the number of protons, neutrons and electrons are
- Radon has 3.8 days as its half-life. How much radon will be left out of 15 mg mass after 38 days?
- The half-life for radioactive decay of 14C is 5730 years. An archaeological artifact containing wood had only 80% of…
- A radioactive element X with half life 2 h decays giving a stable element Y . After a time t , ratio of X and Y atoms…
- A nucleus ruptures into two nuclear parts, which have their velocity ratio equal to 2 : 1. What will be the ratio of…
- Assertion (A): The nucleus _3^7 X is more stable than the nucleus _3^4 X . Reason (R): _3^7 X contains more number of…
- In the question number 66, what would be the angular momentum of H γ photon if the angular momentum of the system is…
- An electron emitted in beta radiation originates from
- A nucleus _z^ A X has a mass represented by M(A, Z). If M p and M n denote the mass of proton and neutron respectively…
- The reaction responsible for the production of light energy from the sun is
- Assertion (A): The binding energy per nucleon is practically constant for mass number in the range ( 30 A 170 ). Reason…
- If the binding energy per nucleon of deuterium is 1.115 MeV, its mass defect in atomic mass unit is
- Suppose we consider a large number of containers each containing initially 10000 atoms of a radioactive material with a…
- Fission of nuclei is possible because the binding energy per nucleon in them
- The mass numbers of two nuclei A and B are 27 and 64 respectively. The ratio of their radii ( r_ A r_ B ) will be:
- A sample of radioactive material has mass m , decay constant λ, molecular weight M and Avogadro constant N A . The…
- Assertion (A): Nuclear fission reactions are responsible for energy generation in the Sun. Reason (R): Light nuclei…
- The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This…
- The mass of 3 7 Li is 0.042 amu less than the sum of masses of its constituents. The binding energy per nuclean is
- The difference in mass of 7 X nucleus and total mass of its constituent nucleons is 21.00 u. The binding energy per…
- Assertion (A): Thermonuclear fusion reactions may become the source of unlimited power for mankind. Reason (R): A…
- The ratio of the nuclear densities of two nuclei having mass numbers 64 and 125 is
- The half life of is 28 years. The disintegration rate of 15 mg of this isotope is of the order of
- The half life of a radioactive substance is 20 s, the time taken for the sample to decay by 7/8 th of its initial value…
- X(n, )_ 3 ^ 7 Li , then X will be
- m , m _ n and m _ p represents masses of aligned & _Z^A X aligned nucleus, a neutron and a proton, respectively. Then:
- Which of the following figures correctly represent the shape of curve of binding energy per nucleon as a function of…
- If the nucleus 13 Al 27 has a nuclear radius of about 3.6 fm, then 52 Te 125 would have its radius approximately as
- How much mass has to be converted into energy to produce electric power of 500 MW for one hour?
- A nucleus of Ux 1 has a half life of 24.1 days. How long a sample of Ux 1 will take to change to 90% of Ux 2 .
- The set which represents the isotope, isobar and isotone respectively is
- A nucleus represented by the symbol A z X has
- The mass number of a nucleus is always less than its atomic number always more than its atomic number sometimes equal…
- M p denotes the mass of a proton and M n that of a neutron. A given nucleus, of binding energy B, contains Z protons…
- When two nuclei (A 10) fuse together to form a heavier nucleus, the:
- The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1 MeV energy is…
- The radius of a spherical nucleus as measured by electron scattering is 3.6 fm. What is the mass number of the nucleus…
- Consider α and β particles and γ-rays each having an energy of 0.5 MeV. In the increasing order of penetrating power…
- The half life of a radioactive substance is 30 days. What is the time taken to disintegrate to 3/4 th of its original…
- Fission of nuclei is possible because the binding energy per nucleon in them increases with mass number at low mass…
- Samples of two radioactive nuclides A and B are taken. λ A and λ B are the disintegration constants of A and B…
- During negative β decay, an antineutrino is also emitted along with the emitted electron. Then,
- The half life period of a radioactive element X is same as the mean life time of another radioactive element Y …
- The radius of _ 13 ^ 27 X nucleus is R. The radius of _ 53 ^ 125 Y nucleus will be
- The count rate of a radioactive sample falls from 4.0 × 10 6 s –1 to 1.0 × 10 6 s –1 in 20 hours. What will be the…
- 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 He 4 is:
- The half life of radioactive radon is 3.8 days. The time at the end of which (1/20) th of the radon sample will remain…
- At a given instant, there are 25% undecayed radioactive nuclei in a sample. After 10 seconds the number of undecayed…
- The half life of polonium is 140 days. In what time will 15 g of polonium be disintegrated out of its initial mass of…
- Two samples X and Y contain equal amount of radioactive substances. If of the sample X and of the sample Y , remain…
- The variation of decay rate of two radioactive samples A and B with time is shown in figure. Which of the following…
- In the reaction _ 1 ^ 2 H + _ 1 ^ 3 H _ 2 ^ 4 He + _ 0 ^ 1 n , if the binding energies of _ 1 ^ 2 H , _ 1 ^ 3 H and _ 2…
- If in a nuclear fusion process the masses of the fusion nuclei be m 1 and m 2 and the mass of the resultant of nucleus…
- When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom
- 1 mg radium has 2.68 × 10 18 atoms. Its half life is 1620 years. How many radium atoms will disintegrate from 1 mg of…
- The equation 4 _ 1 ^ 1 H ^ + _ 2 ^ 4 He ^ 2+ +2 e^ - +26 MeV represents
- A nucleus with mass number 220 initially at rest emits an α particle. If the Q value of the reaction is 5.5 MeV, the…
- It is possible to understand nuclear fission on the basis of the:
- If 200 MeV energy is released in the fission of a single nucleus of 23 5 92 U, the fissions which are required to…
- The mass of proton is 1.0073 u and that of neutron is 1.0087 u ( u = atomic mass unit). The binding energy of He, if…
- In a sample of radioactive material, what fraction of the initial number of active nuclei will remain undisintegrated…
- Which of the following cannot be emitted by radioactive substances during their decay?
- The mass of a _ 3 ^ 7 Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per…
- The half life of 23 8 92 U undergoing α-decay is 4.5 × 10 9 years. The activity of 1 g sample of 23 8 92 U is
- In Rutherford's nuclear model of the atom, the entire positive charge and most of the mass of the atom are concentrated…
- Assertion (A): Unlike electric forces and gravitational forces, nuclear force has limited range. Reason (R): Nuclear…
- A fraction f 1 of a radioactive sample decays in one mean life, and a fraction f 2 decays in one half life. Then
- If the nucleus _ 13 ^ 27 Al has a nuclear radius of about 3.6 fm, then _ 32 ^ 125 Te would have its radius…
- A radioactive decay can form an isotope of the original nucleus with the emission of particles
- Complete the series 6 H e → e + + 6 Li +