Names: Ahmed Ali Saeed Al Sharhan Khalid alneaimi Grade 12-3 Electromagnetic wave

6.1 Describe electromagnetic waves : III. Making Electromagnetic Waves: Recall: EM waves are made by a vibrating charge. This means that a vibrating charge has both an electric. field and a magnetic field. As the charge vibrates, the electric and magnetic fields change. A vibrating electric charge creates an EM wave that travels outward in all directions from the charge. EM waves are transverse waves because the electric and magnetic fields vibrate at right angles to the direction the wave travels.

ELECTROMAGNETIC ENERGY When you tune your radio, watch TV, send a text message, or pop popcorn in a microwave oven, you are using electromagnetic energy. You depend on this energy every hour of every day. Without it, the world you know could not exist. Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays.

6.1.2 Radiant energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by Integrating radiant flux (or power) with respect to time and, like all forms of energy. The term is used particularly when radiation is emitted by a source into the surrounding environment. Radiant energy may be visible or invisible to the human eye.

INFRARED WAVES A remote control uses light waves just beyond the visible spectrum of light—infrared light waves—to change channels on your TV. A typical television remote control uses infrared energy at a wavelength around 940 nanometers.

INFRARED FILM Color Infrared film can record near-infrared energy and can help scientists study plant diseases where there is a change in coloring and cell structure. These two images show the difference between a color infrared photo and a natural color photo of trees and baby in a park.

6.2 Describe electromagnetic spectrum : { Radio waves, television waves, and microwaves are all types of electromagnetic waves. They differ from each other in wavelength. Wavelength is the distance between one wave crest to the next } {The following electromagnetic waves to their frequencies } : Gamma rays: Hz & Higher X-rays: to Hz Ultraviolet waves: to Hz Light waves: 7.85 to 4.85 X Hz Infra red waves: 1 x to 4.3 X Hz Microwaves: 3 X 10 8 to 3 x Hz Radio waves: 3 X 10 4 to 3 X 10 8 Hz

6.2.3 The last line of numbers in power of 10 gives the wavelength in m. The regions sometimes do not have a clear cut, because there is considerable overlap. For example, radio waves and microwaves boundary is very vague, but public regulation for their application (usage) is strict.

6.3 Describe radio communications : Some radio waves carry an audio signal from a radio station to a radio. These radio waves carry information that a radio uses to create sound. You hear a sound wave when the compressions and rarefactions the sound wave produces reach your ears. A radio wave does not needed wires as it travels through air.

6.3.2 Radio waves are electromagnetic waves. Electromagnetic waves include waves such as X rays, ultraviolet light, visible light, infrared rays. Radio waves, including AM radio band, FM radio band, and TV, which uses AM for the picture and FM for the sound.