Answer:
Refer to the explanation.
Step-by-step explanation:
In the context of GCSE Physics, the term "radiation" is usually discussed in relation to electromagnetic radiation and radioactive decay. Here's a breakdown:

Electromagnetic Radiation

Electromagnetic radiation consists of electromagnetic waves that travel through space. These waves can vary in terms of frequency and wavelength. Types of electromagnetic radiation, in order of increasing frequency (or decreasing wavelength), include:
- Radio Waves - Used in radio and television broadcasting.
- Microwaves - Used in microwave ovens and some communication devices.
- Infrared Radiation - Felt as heat and used in heat-sensitive cameras.
- Visible Light - The portion of the spectrum we can see with our eyes.
- Ultraviolet Light - Can cause skin cancer and is used in sterilization.
- X-rays - Used in medical imaging.
- Gamma Rays - Emitted from radioactive materials and are highly penetrating.

Radioactive Decay

When discussing radiation in the context of radioactive materials, you typically encounter three main types of radiation:
- Alpha Radiation (α) - Consists of helium nuclei (2 protons and 2 neutrons). It is the least penetrating but can be highly damaging if ingested.
- Beta Radiation (β) - Consists of high-speed electrons or positrons. More penetrating than alpha particles but less so than gamma radiation.
- Gamma Radiation (γ) - Electromagnetic radiation emitted from a radioactive nucleus. Highly penetrating but generally less damaging to tissues than alpha or beta radiation, per unit of energy absorbed.