A teacher investigates the types of radiation emitted by three radioactive sources, A, B, and C. She does this by measuring the amount of radiation (the count) received by a detector.
She uses the following method:
The teacher then measures the count for each source again, using paper, aluminium, and lead as absorbing materials between the source and the detector.
Name two pieces of equipment that the teacher would need to use in order to measure the count rate in this investigation.
Table 1 shows the results of the teacher's investigation.
Table 1
| Count with no absorber | Count with paper | Count with aluminium | Count with lead | |
|---|---|---|---|---|
| Source A | 950 | 948 | 945 | 25 |
| Source B | 720 | 718 | 22 | 24 |
| Source C | 5400 | 2150 | 26 | 23 |
Copy and complete the table below by ticking (✓\checkmark✓) the boxes to show which types of radiation are emitted by each source.
| Alpha | Beta | Gamma | |
|---|---|---|---|
| Source A | |||
| Source B | |||
| Source C |
Suggest why there is still a count recorded for each source, even when lead is used as an absorbing material.
Another radioactive source, Y, has a half-life of 5 days.
State what is meant by the term half-life.
The initial count rate for source Y is 640 counts per minute640\text{ counts per minute}640 counts per minute. Estimate how many days it will take for the count rate for source Y to fall below 100 counts per minute100\text{ counts per minute}100 counts per minute.
