The document discusses the electromagnetic spectrum and different types of electromagnetic waves. It provides information on light as an electromagnetic wave that can travel through vacuum, and describes the various types of electromagnetic waves including gamma rays, x-rays, ultraviolet, infrared, visible light, microwaves and radio waves. It then discusses some common applications of these different electromagnetic waves such as their use in communication technologies, medical imaging, food heating, remote controls and more.

1. Chapter 17: Part 2: Electromagnetic Spectrum

2. Can light travel through vacuum?

3. Light 1. Light belongs to a special group of waves called Electromagnetic Waves 2. Electromagnetic waves can travel through vacuum. 3. Light is not the only member of Electromagnetic spectrum. There are different types of waves in the spectrum.

4. What is Electromagnetic Spectrum? What is Light spectrum? What is Electromagnetic spectrum? It is a range of colours of light. It is a range of radiation.

5. The Electromagnetic Spectrum Gamma rays X-rays ultraviolet Infrared Visible light Microwaves Radio waves

6. The properties of Electromagnetic Waves They are transverse waves . They do not require medium to travel from one point to another. Thus, they can travel through vacuum. 3. All of them travel at the speed of light of 3.0 x 10⁸ ms -1 in vacuum.

7. Karaoke! What you need to do? Watch Listen Fill in the blanks on the lyrics Sing-along!

8. From the TV station to your living room That is the work of radio waves Heating food in just seconds Microwaves do that Heat treatment for illness Take pictures in the dark They are even in your remote control Infrared radiation Red orange yellow green blue indigo violet That is the only part of the spectrum That can be seen by us The suntan on your skin Kill bacteria and viruses Used to detect forgery That is ultraviolet See your broken bones and my hidden bombs That is the work of x rays Kill cancer cells and sterilize Dangerous gamma rays do that Q: Which one has the highest level of energy?

9. Applications of EM waves

10. Radio waves Radio waves are used for radio communication. A radio tuner is necessary to tune in to a particular frequency to receive certain signals.

11. Radio waves It is also used for broadcasting i.e. television transmission. The antennae on your television set receive the signal, in the form of electromagnetic waves , that is broadcasted from the television station.

12. Radio waves Radiowaves are also used in telecommunication such as cellular phone.

13. Microwaves Microwaves are used in oven to heat up food. Water molecules in food absorb the microwave radiation, thereby heat up.

14. Microwaves Microwaves are also used in telecommunication such as satellite For example, it is used in satellite TV and weather forecast.

15. Infrared Infrared radiation is used in remote controller, commonly for devices such as TVs, DVDs, Home theater systems etc.

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20. Infrared It is also used in thermal imaging The amount of radiation emitted by an object increases with temperature ; therefore, this technique allows one to see variations in temperature.

21. Visible light enables us to see!

22. Visible light Visible light is also used in other imaging technologies such as microscopes, laser and fiber optics.

23. Ultraviolet Ultraviolet could be used to detect forgery.

24. Ultraviolet It is also used in the hospital to sterilise surgical tools i.e. to kill bacteria/viruses.

25. Dangers of UV light Besides being damaging to eyes, over-exposure might also cause skin cancer. Therefore, it is important to protect ourselves from over-exposure of UV radiation.

26. X ray Medical imaging is the technique and process used to create images of the human body for clinical purposes X-ray is often used for this purpose.

27. Gamma radiation Gamma radiation, is electromagnetic radiation of high frequency. Therefore, it is highly damaging to our cells. Despite their cancer-causing properties, gamma rays are also used to treat some types of cancer .