Question 19M.3.sl.TZ2.11
| Date | May 2019 | Marks available | [Maximum mark: 5] | Reference code | 19M.3.sl.TZ2.11 |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | Determine, Outline, State | Question number | 11 | Adapted from | N/A |
This question is about nuclear reactions.
Fission of a nucleus can be initiated by bombarding it with a neutron.
Determine the other product of the fission reaction of plutonium-239.
[1]
[✔]
This question was well answered.
Outline the concept of critical mass with respect to fission reactions.
[1]
minimum mass to «self-»sustain chain reaction
OR
if mass of fissile material is too small, too many neutrons produced pass out of the nuclear fuel
OR
at least one neutron produced causes further reaction [✔]
This question was also fairly well answered although some students missed the concept of maintaining a chain reaction.
Outline one advantage of allowing all countries access to the technology to generate electricity by nuclear fission.
[1]
Any one of:
reduction in emission of greenhouse gases «from burning fossil fuels» [✔]
economic independence/self-sufficiency «from crude oil/producing states» [✔]
uranium is more abundant on Earth «in terms of total energy that can be produced from this fuel» than fossil fuels [✔]
This question was reasonable answered by many students, but some gave very vague or general answers.
State one advantage of using fusion reactions rather than fission to generate electrical power.
[1]
Any one of:
fuel is inexpensive/readily available [✔]
no/less radioactive waste is formed [✔]
lower risk of accidents/large-scale disasters [✔]
impossible/harder to use for making materials for nuclear weapons [✔]
larger amounts of energy released per unit mass [✔]
does not require a critical mass [✔]
can be used continuously [✔]
Note: Accept “higher specific energy for fusion”.
Do not accept “no/less waste produced for fusion”.
Accept specific example for disasters.
This was a well answered question with most student referring to fusion having less or no nuclear waste. There were many different possible correct answers.
90Sr, a common product of fission, has a half-life of 28.8 years.
Determine the number of years for the activity of a sample of 90Sr to fall to one eighth () of its initial value.
[1]
86.4 «years» [✔]
This was a well answered question with most students solving for the number of years correctly.