1. Types of Electromagnetic Radiation and Law of Reflection Chapter 18:2 And Chapter 19.1 page 570

2. Electromagnetic Spectrum Today we know that there is a full range of electromagnetic radiation known as the electromagnetic spectrum. Some of the displays start with the long wavelengths/low frequencies going left to right. Other diagrams may start with the short wavelengths /high frequencies going left to right. In either type of diagram the shorter wavelengths/higher frequencies end with gamma rays and the longer wavelengths/lower frequencies begin with radio waves.

3. The Electromagnetic Spectrum

4. AM and FM Modulation

5. Radio Waves At one end of the spectrum, we have radio waves which have the longest wavelength and the lowest frequency. Wavelengths vary from 1 mm to thousands of kilometers. Radio waves are used in radio and television technologies and in microwave ovens and radar. Radio stations code and transmit information on radio waves through either amplitude modulation (AM stations) or frequency modulation (FM stations).

6. Radar Radar stands for radio detection and ranging. It works by using a radio transmitter sending out short burst of radio waves. The waves bounce off of objects they encounter and the returning signal is picked up and interpreted by a radio receiver. Speeding cars are detected by police radar using the Doppler Effect. The faster a car is moving toward the source, the higher the frequency of the radio waves returning.

7. Microwave Radiation Microwave waves are radio waves that have shorter wavelengths than other radio waves. Their wavelength varies from 1 mm to about 1 meter. Microwaves penetrate foods only a few cm. Water or fat molecules in food absorb microwaves. Instructions that say to let stand for a few minutes are allowing time for conduction to heat the food the rest of the way. Microwaves are also used in cell phone communication.

8. Infrared Rays Infrared rays have higher frequencies than radio waves but lower frequencies than visible red light. Infrared rays are used as a source of heat and to discover areas of heat differences. A device called a thermograph uses infrared sensors to create thermograms which are color- coded pictures that show variations in temperature. They are used to see how a building is losing heat, or to locate problems in the path of an electric current, or to find human bodies even underground after an earthquake. Infrared lamps are used to keep foods warm in restaurants or to keep reptile habitats warm at zoos.

9. Infrared Radiation

10. Visible Light In visible light each color has a different wavelength and frequency. The rainbow of colors in this visible part of the spectrum can be remembered by “Roy G. Biv” which stands for red, orange, yellow, green, blue, indigo and violet. Red is the longest wavelength but wavelength gets shorter until violet which has the shortest wavelength. Visible light is so important to us because it allows us to read, to enjoy color, to be safe at traffic lights, and to grow plants at the base of the food chain.

11. Visible Light Frequencies

12. Ultraviolet Rays Ultraviolet radiation has a higher frequency and shorter wavelength than violet in the visible light part of the spectrum. Ultraviolet rays in moderation produce helps your skin produce vitamin D which aids in the absorption of calcium. Ultraviolet rays are used to kill microorganisms. In fact they are used in heating and cooling systems to disinfect the air flow in large buildings. Ultraviolet radiation has a higher frequency and shorter wavelength than violet in the visible light part of the spectrum. Ultraviolet rays in moderation produce helps your skin produce vitamin D which aids in the absorption of calcium. Ultraviolet rays are used to kill microorganisms. In fact they are used in heating and cooling systems to disinfect the air flow in large buildings. The down side is that too much exposure causes sunburns, wrinkles, and eventually skin cancer. The down side is that too much exposure causes sunburns, wrinkles, and eventually skin cancer.

13. X-Rays X-rays have higher frequencies and shorter wavelengths than ultraviolet rays. X-rays have higher frequencies and shorter wavelengths than ultraviolet rays. X-rays are used in medicine, industry, and transportation to make pictures of the inside of solid objects. X-rays are used in medicine, industry, and transportation to make pictures of the inside of solid objects. The higher energy of x-rays enable them to penetrate matter that light cannot. X-ray photographs show softer tissue as dark, highly exposed areas but will show bones and teeth as white. Too much exposure to x-rays can kill or damage living tissue. X-rays also enable airport security to see what may be inside a suitcase without opening them. The higher energy of x-rays enable them to penetrate matter that light cannot. X-ray photographs show softer tissue as dark, highly exposed areas but will show bones and teeth as white. Too much exposure to x-rays can kill or damage living tissue. X-rays also enable airport security to see what may be inside a suitcase without opening them.

14. X-Ray Picture

15. Gamma Rays Gamma rays have the shortest wavelengths, the greatest frequencies, the most energy, and the greatest penetrating ability of all of the electromagnetic waves. Gamma rays have the shortest wavelengths, the greatest frequencies, the most energy, and the greatest penetrating ability of all of the electromagnetic waves. Exposure to tiny amounts of gamma rays are tolerable, but overexposure can be deadly. Exposure to tiny amounts of gamma rays are tolerable, but overexposure can be deadly. Gamma rays are used in the medical field to kill cancer cells and make pictures of the brain, and in industrial situations as an inspection tool. Machines that travel on the inside of a pipe take gamma ray pictures along the length to detect rusting, cracks, or other signs of damage. Gamma rays are used in the medical field to kill cancer cells and make pictures of the brain, and in industrial situations as an inspection tool. Machines that travel on the inside of a pipe take gamma ray pictures along the length to detect rusting, cracks, or other signs of damage.

16. The Law of Reflection A ray diagram shows how rays change direction when they strike mirrors and pass through lens. A ray diagram shows how rays change direction when they strike mirrors and pass through lens. The incident ray is the incoming ray. The angle of incidence is the angle the incident ray makes with a line drawn perpendicular to the surface of the mirror. The mirror reflects the incident ray. The angle of reflection is the angle of the reflected ray makes with the perpendicular line. The law of reflection states that the angle of reflection is equal to the angle of incidence. The incident ray is the incoming ray. The angle of incidence is the angle the incident ray makes with a line drawn perpendicular to the surface of the mirror. The mirror reflects the incident ray. The angle of reflection is the angle of the reflected ray makes with the perpendicular line. The law of reflection states that the angle of reflection is equal to the angle of incidence.

17. Law of Reflection