Nuclei-Quiz-8

 

 

NUCLEI QUIZ-8

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. Given a sample of Radium-226 having half-life of 4 days. Find the probability, a nucleus disintegrates after 2 half lives span

•  1
•   1/2
•   1.5
•   3/4

Solution

Q2 The equation 4_1^1 H→ _2^4 He^2+2e^-+26 MeV represents

•   β-decay
•   γ-decay
•   Fusion
•   Fission

Solution

 (c) 〖4 〗_1^1 H^+→ _2^4 He^(2+)+2e^-+26 MeV represents a fusion reaction

Q3A neutron of energy 1 MeV and mass 1.6×10^(-27) kg passes a proton at such a distance that the angular momentum of the neutron relative to the proton approximately equals 10^(-33) Js. The distance of closest approach neglecting the interaction between particles isspan

•   0.44 nm
•   0.44 mm
•   0.44 Å
•   0.44 fm

Solution

Q4 There are two ratio nuclei A and B. A is an alpha emitter and B a beta emitter. Their disintegration constants are in the ratio of 1:2. What should be the ratio of number of atoms of A and B at any time t so that probabilities of getting alpha and beta particles are same at that instant?

•   2:1
•   1:2
•   e
•   e^(-1)

Solution

Q5. The following deuterium reactions and corresponding reaction energies are found to occur ^14 N (d,p) ^15 N Q=8.53 MeV ^15 N (d,α) ^13 C Q=7.58 MeV ^13 C (d,α) ^11 B Q=5.16 MeV The rotation ^14 N(d,p) ^15 N represents the reaction ^14 N+d→ ^15 N+p _2^4 He=4.0026 a.m.u.,_1^2 He=2.014 a.m.u.,_1^1 H=1.0078 a.m.u.,n=1.0087 a.m.u. (1 a.m.u.=931 MeV) The Q values of the reaction ^11 B(α,n) ^14 N is

•   0.5 eV
•   0.5 MeV
•   0.05 MeV
•   0.05 eV

Solution

Q6A radioactive sample decays by 63% of its initial value in 10 s. It would have decayed by 50% of its initial value in span

•  7 s
•  14 s
• 0.7 s
•  1.4 s

Solution

 

Q7. Assuming that about 200 MeV of energy is released per fission of 〖 _92 H〗^235 nuclei, the mass of 〖 _ U〗^235 consumed per day in a fission reactor of power 1 megawatt will be approximately

•   10^(-2) g
•   1 g
•   100 g
•   10,000 g

Solution

Q8 In a sample of rock; the ratio of ^206 Pb to ^238 U nuclei is found to be 0.5. The age of the rock is (given half-life of U^238 is 4.5×10^9 years)

•   2.25×10^9 year
•   4.5×10^9 ln⁡3 year
•   4.5×10^9 ln⁡(3/2)/ln⁡2 year
•  2.25×10^9 ln⁡(3/2) year

Solution

 

Q9. The binding energy of deuteron _1^2 H is 1.112 MeV per nucleon and an α-particle _2^4 He has a binding energy of 7.047 MeV per nucleon. Then in the fusion reaction _1^2 H+ _1^2 H→_2^4 He+Q, the energy Q released is

•   1 MeV
•   11.9 MeV
•   23.8 MeV
•   931 MeV

Solution

 

Q10. The half-life of ^131 I is 8 days. Given a sample of ^131 I at time t=0, we can assert that

•  No nucleus will decay before t=4 days
•  No nucleus will decay before t=8 days
• All nuclei will decay before t=16 days
• A given nucleus may decay at any time after t=0
  
  

Solution