Discussion
Which among the following nuclei are fissile ?
(I) 233U
(II) 238U
(III) 239Pu
(IV) 235U
Answer: C
The fissile nuclei are (I), (III) and (IV): 233U, 239Pu and 235U.
A fissile nucleus can be split by slow (thermal) neutrons and sustain a chain reaction. Nuclei with an odd number of neutrons, such as 233U (141 neutrons), 235U (143) and 239Pu (145), gain enough pairing energy on capturing a neutron to exceed the fission barrier, so even a slow neutron triggers fission.
238U, with 146 neutrons, is not fissile. It fissions only with fast neutrons and is called fertile, because neutron capture turns it into 239Pu; likewise 232Th breeds 233U. Every option that includes (II) therefore lists a non-fissile nucleus.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development