Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Identifying radiation using absorbing barriers
A teacher wanted to find out what nuclear radiation is emitted from a source. The teacher placed different barriers between the source and a detector. The teacher recorded the count for 30 seconds after each barrier was put in place. Table 2 shows the results.
Explain what nuclear radiation was emitted by the source.
Practice unavailable
This question can be viewed, but its original response format is not available for practice yet.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 State that some radiation is stopped by paper.
- 2 Use this to infer that alpha radiation is emitted.
- 3 State that some radiation passes through paper but is stopped by aluminium.
- 4 Use this to infer that beta radiation is emitted and gamma radiation is not emitted.
Full-mark answer
Some of the radiation is stopped by paper, so the source emits alpha radiation. Some radiation passes through paper but is stopped by aluminium, so the source also emits beta radiation. Since the count is zero after aluminium, the source does not emit gamma radiation.
Why this answer loses marks
The source emitted alpha radiation because paper stopped the count.
This uses the paper result but ignores the remaining count after paper and the fact that aluminium reduced the count to zero, which shows beta radiation was also present and gamma was not.