**NUCLEI QUIZ-3****Dear Readers,**

JEE Advanced Physics Syllabus can be referred by the IIT aspirants to get a detailed list of all topics that are important in cracking the entrance examination. JEE Advanced syllabus for Physics has been designed in such a way that it offers very practical and application-based learning to further make it easier for students to understand every concept or topic by correlating it with day-to-day experiences. In comparison to the other two subjects, the syllabus of JEE Advanced for physics is developed in such a way so as to test the deep understanding and application of concepts.

**Q1. A radioactive nucleus A finally transforms into a stable nucleus B. Then, A and B may be**

Solution

(c)
A and B can be isotopes if number of Î²-decays is two times the number of Î±-decays

**Q2. As per Bohr model, the minimum energy (in eV) required to remove an electron from the ground state of doubly ionized Li atom (Z=3) is**

**Q3. Masses of two isobars _29 Cu^64 and _30 Zn^64 are 63.9298 u and 63.9292 u, respectively. It can be concluded from these data that**

Solution

3 (c) By the conservation of charge and nucleons, only potential is feasible

3 (c) By the conservation of charge and nucleons, only potential is feasible

**Q4. Binding energy per nucleon for C^12 is 7.68 MeV and for C^13 is 7.74 MeV. The energy required to remove a neutron from C^13 is**

Solution

4 (b) The difference in the binding energies is the energy required to add an extra neutron

4 (b) The difference in the binding energies is the energy required to add an extra neutron

**Q5. A radioactive sample S1 having an activity of 5Î¼Ci has twice the number of nuclei as another sample S2 which has an activity of 10Î¼Ci. The half lives of S1 and S2 can be**

**Q6.The luminous dials of watches are usually made by mixing a zinc sulphide phosphor with an Î±-particle emitter. The mass of radium (mass number 226, half-life 1620 years) that is needed to produce an average of 10 Î±-particles per second for this purpose is**

**Q7. Calculate the binding energy of a deuteron atom, which consists of a proton and a neutron, given that the atomic mass of the deuteron is 2.014102 u**

Solution

7 (d) Atomic mass M(H) of hydrogen and nuclear mass (M_n) are M(H)=1.007825 u and M_n=1.008665 u Mass defect, ∆m=[M(H)+M_n-M(D)] M(D)= mass of deuteron =2.016490 u-2.014102 u=0.002388 u As 1 u corresponds to 931.494 MeV energy, therefore, mass defect corresponds to energy, E_b=0.002388×931.5=2.224 MeV

7 (d) Atomic mass M(H) of hydrogen and nuclear mass (M_n) are M(H)=1.007825 u and M_n=1.008665 u Mass defect, ∆m=[M(H)+M_n-M(D)] M(D)= mass of deuteron =2.016490 u-2.014102 u=0.002388 u As 1 u corresponds to 931.494 MeV energy, therefore, mass defect corresponds to energy, E_b=0.002388×931.5=2.224 MeV

**Q8 A radioactive substance X decays into another radioactive substance Y. Initially, only X was present. Î»_x and Î»_y are the disintegration constants of X and Y. N_y will be maximum when**

**Q9 A proton and a neutron are both shot at 100 ms^(-1) towards a _6^12 C nucleus. Which particle, if either, is more likely to be absorbed by the nucleus?**

Solution

**(b)**

**Q10 To determine the half- life of radioactive element, a student plots graph of ln|(dN (t))/dt|versus t. Here (dN (t))/dt is the rate of radioactive decay at time t. If the number of radioactive nuclei of this element decreases by a factor of p after 4.16 yr, the value of p is**