Worksheet Chapter 8: Radioactivity

1. Radioisotopes are widely used in modern industry and medicine. State the specific radioisotope used for:
(a) Radiotherapy cancer treatment.
(b) Carbon dating organic fossils.
(c) Detecting underground pipe leakage.
(d) Controlling paper thickness in manufacturing.

2. Which of the following radiation types has the highest penetrating power?

3. True or False: Alpha particles carry a negative charge and are attracted toward the positive plate in an electric field.

4. State three practical safety precautions that must be observed when handling radioactive substances in a laboratory or hospital setting.

5. True or False: Non-ionising radiation such as visible light and radio waves possesses sufficient energy to remove electrons from neutral atoms.

6. A scientist measures a radioactive substance's activity over time and records the following data:
- 0 hours: 1600 Bq
- 4 hours: 800 Bq
- 8 hours: 400 Bq
- 12 hours: 200 Bq
(a) Determine the half-life of this substance.
(b) Calculate the remaining mass percentage of the sample after 16 hours.

7. Fill in the blank: The time taken for a radioactive sample's activity to decrease to half of its original value is known as its ____________.

8. State the unit used to measure equivalent radiation dosage absorbed by human tissue.

9. Compare Alpha, Beta, and Gamma radiation in terms of their penetrating power and the materials required to stop them.

10. A radioactive isotope has a half-life of 6 hours. If the initial activity of the sample is 640 Bq, calculate its remaining activity after 18 hours.