Nuclei-Quiz-7

 

 

NUCLEI QUIZ-7

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 The fraction of a radioactive material which remains active after time t is 9/16. The fraction which remains active after time t/2 will be:

•   4/5
•   7/8
•   3/5
•   3/4

Solution

Q2. Which of the following is in the increasing order for penetrating power

•   α,β,γ
•   β,α,γ
•   γ,α,β
•   γ,β,α

Solution 

(a) Penetration power of γ is 100 times of β, while that of β is 100 times of α

Q3. Assuming that about 20 MeV of energy is released per fusion reaction 〖 _1 H〗^2+〖 _1 H〗^2→+〖 _2 He〗^4+E+ other particles Then the mass of 〖 _1 H〗^2 consumed per day in a fusion reactor of power 1 megawatt will approximately be

•   0.001 g
•   0.1 g
•   10.0 g
•   1000 g

Solution

Q4 A radioactive sample S_1 having an activity of 5μCi has twice the number of nuclei as another sample S_2 which has an activity of 10 μCi. The half lives of S_1 and S_2 can be

•   20 yr and 5 yr ,respectively
•   20 yr and 10 yr ,respectively
•   10 yr each
•   5 yr each

Solution

Q5. Consider two arbitrary decay equations and mark the correct alternative(s) given below: _92^230 U→n+ _92^229 U _92^230 U→p+ _91^229 U Given: M( _92^230 U)=230.033927 u, M( _92^229 U)=229.03349 u,m_n=1.008665 u, M( _91^229 Pa)=229.032089,m_p=1.007825,1 a.m.u=931.5 MeV

•   Only decay (i) is possible
•   Only decay (ii) is possible
•   Both the decays are possible
•   Neither of the two decays is possible

Solution

Q6. 1.00 kg of ^235 U undergoes fission process. If energy released per event is 200 MeV, then the total energy released is 

•   5.12×10^24 MeV
•   6.02×10^23 MeV
•   5.12×10^26
•   6.02×10^26 MeV

Solution

Q7.  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 sample after two mean lives i

•   1.35 g
•   2.50 g
•   3.70 g
•   6.30 g

Solution

Q8 The activity of a radioactive element decreases to one-third of the original activity I_0 in a period of nine years. After a further lapse of nine years, its activity will be b>

•   I_0
•   (2/3)I_0
•   (I_0/9)
•   (I_0/6)

Solution

Q9. During a negative beta decay

•   An atomic electron is ejected
•   An electron which is already present within the nucleus is ejected
•   A neutron in the nucleus decays emitting an electron
•   A part of the binding energy of the nucleus is converted into an electron

Solution 

(c) Following nuclear reaction takes place 〖 _0 n〗^(-1) ⇒_ 〖 _1 H〗^1+〖 _(-1) e〗^0+v ̅

Q10. The binding energy per nucleon of O^16 is 7.97MeV and that of O^17 is 7.75 MeV. The energy (in MeV) required to remove a neutron from O^17 is

• 3.52 
•   3.52
• 4.23
• 7.86
  
  

Solution

(c) The equation is O^17 →_0 n^1+O^16 ∴ Energy required = B.E. of O^17- B.E. of O^16 =17×7.75-16×7.97=4.23 MeV