The Electromagnetic Spectrum
Overview
Your eyes are extraordinary instruments, and they are also very nearly blind. The light they detect is a sliver of a much wider family of waves that fills the room you are sitting in right now: radio signals, the warmth from a radiator, the ultraviolet slipping through the window.
This lesson sets out the seven regions of the electromagnetic spectrum in order, shows what each one is used for, and explains why the same family that lets a surgeon see a broken bone can also give you skin cancer if you treat it carelessly.
Objectives
- Know that light is part of a continuous electromagnetic spectrum that includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space
- Know the order of the electromagnetic spectrum in terms of decreasing wavelength and increasing frequency, including the colours of the visible spectrum
- Explain some of the uses of electromagnetic radiations, including radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays
- Explain the detrimental effects of excessive exposure of the human body to electromagnetic waves and describe simple protective measures against the risks
Mind map
This topic is mapped out so you can see how the ideas connect.
Open the mind map in the app
Flashcards
Quick recall practice on the facts this topic is tested on.
Practise these cards in the app
Lesson Note
Complete Note Available on the Green Bridge App
Get the Green Bridge CBT app on your phone or computer for the complete IGCSE library: past papers, mark schemes, mind maps, flashcards and audio lessons.
Lesson Evaluation
Congratulations on completing the lesson on The Electromagnetic Spectrum. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which of the following lists the electromagnetic spectrum in order of decreasing wavelength? A) Gamma, X-ray, ultraviolet, visible, infrared, microwave, radio B) Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma C) Radio, infrared, microwave, visible, X-ray, ultraviolet, gamma D) Visible, infrared, radio, microwave, ultraviolet, X-ray, gamma Answer: B
- In free space, all electromagnetic waves have the same: A) wavelength B) frequency C) speed D) energy Answer: C
- Which colour of visible light has the shortest wavelength? A) Red B) Green C) Blue D) Violet Answer: D
- Which region of the spectrum is used in thermal imaging cameras? A) Radio waves B) Infrared C) Ultraviolet D) Gamma rays Answer: B
- Excessive exposure to ultraviolet radiation is most likely to cause: A) internal heating of tissue B) skin cancer and eye damage C) no harmful effects D) broken bones Answer: B
Work through these questions in the app
Work through these questions in the app
Practice Mock Questions
Want to practice mock questions on The Electromagnetic Spectrum? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
Download The App On Google Playstore
Everything you need to excel in your exams
