---
title: "The Electromagnetic Spectrum: Uses and Dangers"
description: "The seven groups run from radio waves to gamma rays in order of increasing frequency, all travelling at the same speed through space. Each group has uses that follow from how it interacts with matter,"
canonical: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-uses-and-dangers-mt_P_NXNSo1zQ
source: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-uses-and-dangers-mt_P_NXNSo1zQ.md
retrieved: 2026-09-12
---

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# The Electromagnetic Spectrum: Uses and Dangers

The seven groups run from radio waves to gamma rays in order of increasing frequency, all travelling at the same speed through space. Each group has uses that follow from how it interacts with matter, and the high-frequency end is ionising.

Subject: Science · Area: Waves, Light & Sound · Ages 15 to 16
Page: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-uses-and-dangers-mt_P_NXNSo1zQ

## Ready when they can

- Puts the seven groups in order and pairs each with a use that fits its properties
- Explains which groups are ionising and what harm ultraviolet, X-rays and gamma rays can do
- Justifies a choice of radiation for a job, such as cooking, imaging or communication

## Lesson: From radio waves to gamma rays

Sunlight looks white until a prism splits it into a rainbow, and that visible band is one thin slice of a wider family. The order runs radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. Every member travels at the same speed in empty space, with frequency rising as wavelength shrinks.

**Example.** Ada matches each group to its job. Long radio waves carry broadcasts and phone signals, microwaves heat food and drive radar, and infrared warms heaters and carries remote signals. Ultraviolet tans skin, X-rays see through soft tissue to image bones, and gamma rays trace pipes and treat cancer.

Radiation only means energy travelling through space, and most of it is harmless. The danger starts where photons can ionise atoms: ultraviolet, X-rays and gamma rays. That is why sunburn warns you about UV while nobody fears the radio playing beside you.

**Tip.** Pick the radiation by the job. Long wavelength means low energy and suits signalling. Short wavelength means high energy and penetration, so it suits imaging, sterilising and cancer treatment. Never send ionising rays where a safer band can do the work.

**Recap.** Seven groups in order, each with jobs set by its energy.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Protecting Eyes from Sunlight](https://lightmysky.com/learn/science/protecting-eyes-from-sunlight-mt_3yuqKww2tU)
- [Nuclear Fission and Fusion](https://lightmysky.com/learn/science/nuclear-fission-and-fusion-mt_jkO89KodSb)
- [Waves & Different Materials](https://lightmysky.com/learn/science/waves-and-different-materials-mt_w5HzPpOUmj)
- [The Wave Equation](https://lightmysky.com/learn/science/the-wave-equation-mt_wmKhTiXt1p)
- [The Electromagnetic Spectrum](https://lightmysky.com/learn/science/the-electromagnetic-spectrum-mt_XSp-S0wter)

## Opens up

- [The Layered Atmosphere and Why Temperature Reverses With Height](https://lightmysky.com/learn/science/the-layered-atmosphere-and-why-temperature-reverses-with-height-mt_2icQ747JhN)
- [NMR Spectra: Counting Environments](https://lightmysky.com/learn/science/nmr-spectra-counting-environments-mt_JquoiaxOMu)
- [Free-Radical Substitution in Alkanes](https://lightmysky.com/learn/science/free-radical-substitution-in-alkanes-mt_QkreYC9e2d)
- [Photon Energy and the Electronvolt](https://lightmysky.com/learn/science/photon-energy-and-the-electronvolt-mt_UfmDhGRaYT)
- [Infrared Emission, Absorption and the Temperature of a Body](https://lightmysky.com/learn/science/infrared-emission-absorption-and-the-temperature-of-a-body-mt_xwh9uZ8gCl)