Section 1 of 4Hazards by Region
Each region of the spectrum causes a different kind of harm when a person is overexposed to it.
Microwaves
- Microwaves can heat body tissue internally, causing damage to internal organs.
Infrared
- Infrared is absorbed by the skin as thermal energy, so overexposure can burn the skin.
Ultraviolet
- Ultraviolet damages skin cells, causing sunburn, and can damage the eyes, potentially leading to blindness.
X-rays and gamma rays
- These can kill cells and cause cancer or cell mutations, because they ionise atoms inside the body.
Section 2 of 4Energy and Ionisation
1
As the frequency of an electromagnetic wave increases, the energy carried by each wave also increases.
2
Beyond the visible part of the spectrum, the energy of the waves becomes large enough to ionise atoms.
3
Ionisation of atoms in cells can damage DNA, which can lead to mutations or cancer.
4
The shorter the wavelength, the more ionising the radiation is, so gamma rays are the most dangerous.
Section 3 of 4Protective Measures
Protective Measures
Microwave shielding
- The metal walls and metal grid in the glass door of a microwave oven keep the microwaves inside the oven.
Sun protection
- Sunglasses absorb ultraviolet to protect the eyes, and sunscreen absorbs it to protect the skin.
X-ray dose control
- Doctors use the minimum X-ray dose needed, leave the room during the exposure, and radiographers wear radiation badges.
Gamma ray monitoring
- People working with gamma rays have their radiation dose levels tested routinely.
Section 4 of 4Exam Checklist & Tips
3.1.7 – Key Points for the Exam
- Ionisation The process of removing electrons from atoms, which the most energetic electromagnetic waves can cause.
- Ionising radiation Radiation with enough energy to ionise atoms, such as X-rays and gamma rays.
- Radiation badge A device worn by people working with radiation to monitor their exposure.
- Overexposure Receiving more radiation than is safe, which can cause tissue damage.
- Mutation A change in the DNA of a cell, which can be caused by ionising radiation.
Common Mistakes
- Saying that all electromagnetic waves are equally dangerous; the hazard increases with frequency.
- Claiming that visible light is as dangerous as gamma rays; visible light is far less hazardous.
- Giving a general safety statement instead of naming a specific measure for each type of hazard.
- Confusing the heating danger of infrared with the ionising danger of X-rays and gamma rays.