Nuclei-Quiz-5

 

NUCLEI QUIZ-5

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 If a star can convert all the He nuclei completely into oxygen nuclei, the energy released per oxygen nuclei is ( Mass of the nucleus is 4.0026 amu and mass of oxygen nucleus is 15.9994 amu)

•  7.6MeV
  
• 56.12MeV
  
• 10.24MeV
• 23.9MeV

Solution

Q2.

Half-lives of two radioactive substances A and B are, respectively, 20 min and 40 min. Initially, the samples of A and B have equal number of nuclei.  After 80 min, the ratio of the remaining number of A and B nuclei is

•   1:16
•   4:1
•   1:4
•   1:1

Solution

Q3 The activity of a radioactive sample is 1.6 curie, and its half-life is 2.5 days. Its activity after 10 days will be

•   0.8 curie
•   0.4 curie
•   0.1 curie
•   0.16 curie 

Solution

Q4 What is the age of an ancient wooden piece if it is known that the specific activity of C^14 nuclide in it amounts to 3/5 of that in fresh trees? Given: the half of C nuclide is 5570 years and log_e⁡〖(5/3)=0.5〗

•  0 years
•  2000 years
•  3000 years
•  4000 years

Solution

Q5 A sample of radioactive material decays simultaneously by two processes A and B with half-lives 1/2 and 1/4 h, respectively. For first half hour it decays with the process A, next one hour with the process B, and for further half an hour with both A and B. If originally there were N_0 nuclei, find the number of nuclei after 2 h of such decay

• N_0/(2)^8
• N_0/(2)^4
• N_0/(2)^6
• N_0/(2)^5

Solution

Q6. A radioactive element X converts into another stable element Y. Half-life of X is 2 h. Initially, only X is present. After time t, the ratio of atoms of X and Y is found to be 1:4. Then t in hours is 

•  2
•  4
• Between 4 and 6
•  6

Solution

Q7. Binding energy per nucleon of 〖 _1 H〗^2 and 〖 _2 He〗^4 are 1.1 MeV and 7.0 MeV, respectively. Energy released in the process 〖 _1 H〗^2+〖 _1 H〗^2=〖 _2 He〗^4 is

•   20.8 MeV
•   16.6 MeV
•   25.2 MeV
•   23.6 MeV

Solution

 

Q8A hydrogen like atom of atomic number Z is in an excited state of quantum number 2n. It can emit a maximum energy photon of 204 eV. If it makes a transition to quantum state n, a photon of energy 40.8 eV is emitted. The value of n will be

•  1
•  2
•  3
•  4

Solution

Q9. _19^49 K isotope of potassium has a half-life of 1.4×10^9 yr and decays to form stable argon, _18^40 Ar. A sample of rock has been taken which contains both potassium and argon in the ratio 1:7, i.e., (Number of potassium-40 atoms)/(Number of argon-40 atom)=1/7 Assuming that when the rock was formed no argon-40 was present in the sample and none has escaped subsequently, determine the age of the rock

•   4.2×10^9 years
•   9.8×10^9 years
•   1.4×10^9 years
•   10×10^9 years

Solution

Q10. During a nuclear fusion reaction

• A heavy nucleus breaks into two fragments by itself 
• A light nucleus bombarded by thermal  
• A heavy nucleus bombarded by thermal
• Two light nuclei combine to give a heavier nucleus and