Nuclear reactions as a source of energy
3 marks · NormalIn the fission of uranium-235, different numbers of neutrons can be released depending on the fission event. The table below shows data from five fission events.
| Fission event | Number of neutrons released |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 3 |
| 4 | 2 |
| 5 | 4 |
Calculate the average number of neutrons released per fission event in this sample.
Explain why the actual number of neutrons released per fission can vary between events.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 2.8
(b) Because the process is random and different fission paths produce different numbers of neutrons.
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Adds the numbers and divides by 5.
A1 (a) · 1 mark · Obtains correct value 2.8. (follow-through)
B1 (b) · 1 mark · Explains that randomness of fission and different ways the nucleus can split lead to different numbers of neutrons.
Worked solution
a) Total neutrons = 2 + 3 + 3 + 2 + 4 = 14.
b) The number varies because the splitting process is random; the nucleus can split in different ways, producing different numbers of neutrons.