Edexcel iGCSE Physics -7.14 Uses of Radioactivity- Study Notes- New Syllabus
Edexcel iGCSE Physics -7.14 Uses of Radioactivity- Study Notes- New syllabus
Edexcel iGCSE Physics -7.14 Uses of Radioactivity- Study Notes -Edexcel iGCSE Physics – per latest Syllabus.
Key Concepts:
update
Uses of Radioactivity in Industry and Medicine
Radioactive substances are used in many areas of industry and medicine. These uses depend on the penetrating power, ionising ability, and half-life of the radiation.
Key Idea
Different types of radiation are chosen for different applications because they interact with matter in different ways.
Uses of Radioactivity in Industry
1. Thickness Control
- Used in paper, aluminium, and plastic production.
- A radioactive source is placed on one side of the material.
- A detector is placed on the opposite side.
- Changes in count rate indicate changes in thickness.
Key idea: Beta radiation is commonly used because it is partially absorbed.
2. Leak Detection in Pipes
- A radioactive tracer is added to a fluid.
- The fluid flows through pipes.
- Radiation is detected outside the pipe.
- A sudden increase in count rate indicates a leak.
Key idea: Gamma radiation is used because it can pass through pipes and soil.
3. Sterilisation of Equipment and Food
- Gamma radiation kills bacteria and microorganisms.
- Used to sterilise medical equipment.
- Used to sterilise food and increase shelf life.
Important: The food does not become radioactive.
Uses of Radioactivity in Medicine
1. Medical Tracers
- Radioactive tracers are injected or swallowed.
- Gamma radiation is detected outside the body.
- Used to study organ function.
Key idea: Gamma radiation escapes the body easily and causes low ionisation.
2. Treating Cancer (Radiotherapy)
- High-energy radiation is aimed at cancer cells.
- Radiation damages the DNA of cancer cells.
- This stops cells dividing and kills them.
Important:
- Gamma radiation is commonly used.
- Doses are carefully controlled to reduce damage to healthy cells.
3. Sterilising Medical Equipment
- Gamma radiation is used to sterilise syringes and surgical tools.
- Ensures equipment is free from bacteria.
Choosing the Right Radiation
| Radiation | Typical use | Reason |
|---|---|---|
| Alpha | Smoke detectors | Strongly ionising, short range |
| Beta | Thickness control | Partially absorbed |
| Gamma | Medical tracers, radiotherapy | Highly penetrating |
Summary
- Radioactivity has important industrial and medical uses.
- Industry uses radiation for control, detection, and sterilisation.
- Medicine uses radiation for diagnosis and treatment.
- Each use depends on penetration and ionisation properties.
Example
Explain why beta radiation is suitable for controlling the thickness of aluminium sheets in industry.
▶️ Answer / Explanation
- Beta radiation is partially absorbed by aluminium.
- If the sheet becomes thicker, less radiation reaches the detector.
- If the sheet becomes thinner, more radiation is detected.
- This allows automatic thickness control.
Example
Explain why gamma radiation is used both as a medical tracer and in cancer treatment.
▶️ Answer / Explanation
- Gamma radiation is highly penetrating.
- It can pass out of the body to be detected externally.
- High-energy gamma rays can damage cancer cells.
- Doses can be controlled to limit harm to healthy tissue.