Edexcel iGCSE Physics -7.10 Background Radiation- Study Notes- New Syllabus
Edexcel iGCSE Physics -7.10 Background Radiation- Study Notes- New syllabus
Edexcel iGCSE Physics -7.10 Background Radiation- Study Notes -Edexcel iGCSE Physics – per latest Syllabus.
Key Concepts:
update
Sources of Background Ionising Radiation
Background radiation is the low-level ionising radiation that is always present in the environment. It comes from both natural sources on Earth and from outer space.
Key Statement
Statement: Background ionising radiation comes from radioactive materials in the Earth and from radiation originating in space.
Key idea: Background radiation is always present, even when no artificial radioactive sources are nearby.
Sources of Background Radiation from the Earth
1. Rocks and Soil
- Contain naturally occurring radioactive elements.
- Examples include uranium and thorium.
- These emit alpha, beta, and gamma radiation.
Key point: Some areas have higher background radiation due to local geology.
2. Radon Gas
- Radon is a radioactive gas formed from the decay of uranium in rocks.
- It can seep into buildings from the ground.
- It is a major contributor to background radiation.
Key idea: Radon increases indoor background radiation levels.
3. Living Things
- Small amounts of radioactive isotopes are found in living organisms.
- These are absorbed from food and water.
- Example: radioactive carbon.
Important: This radiation comes from inside the body.
Sources of Background Radiation from Space
Cosmic Radiation
- High-energy radiation enters Earth’s atmosphere from space.
- Originates from the Sun and distant stars.
- Produces secondary radiation when it interacts with the atmosphere.
Key points:
- Cosmic radiation increases with altitude.
- People in aircraft receive higher exposure.
- The atmosphere provides shielding.
Why Background Radiation Varies
- Type of local rocks.
- Presence of radon gas.
- Altitude above sea level.
- Time spent indoors or outdoors.
Key idea: Background radiation level is not the same everywhere.
Example
Explain why people living in mountainous regions experience higher background radiation levels than those living at sea level.
▶️ Answer / Explanation
- Cosmic radiation comes from space.
- The atmosphere absorbs some of this radiation.
- At higher altitudes there is less atmosphere.
- More cosmic radiation reaches the ground.
Example
A house has higher background radiation levels indoors than outdoors. Suggest and explain a likely cause.
▶️ Answer / Explanation
- Radon gas may be entering the house from the ground.
- Radon is radioactive.
- It can build up indoors.
- This increases the background radiation level.