Chapter 16 electronics and information and communication technology (ict)
CHAPTER 16- ELECTRONICS AND INFORMATIONAND COMMUNICATION TECHNOLOGY
WAVES…. generated by forces that cause vibrations or oscillations to a system...tranferenergy from one point to another.
TWO TYPE OF WAVESMECHANICAL WAVES ELECTROMAGNETIC WAVES
MECHANICAL WAVES …. generated vibrations or oscillations of particles or object.example: sound waves ….require a medium to travel in, travel through solid ( wall ), through liquid ( water ), through gases (atmosphere ). cannot through a vacumm ( outer space)
About Electromagnetic Waves When you listen to the radio, watch TV, or cook dinner in a microwave oven, you are using electromagnetic waves. 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.
Properties of ElectromagneticWaves Electromagnetic Wave- A transverse wave consisting of oscillating electric and magnetic fields at right angles to each other The spectrum includes more than visible light- not all light is visible to the human eye Light is a wave and also a particle
The Electromagnetic Spectrum Electromagnetic waves vary depending on frequency and wavelength
Properties of the Electromagnetic Spectrum Waves in the electromagnetic spectrum vary in size from very long radio waves the size of buildings, to very short gamma-rays smaller than the size of the nucleus of an atom.
Properties of the Electromagnetic Spectrum FREQUENCY – is the number of waves generated per unit time. OR …number of crest or troughs passing through aWAVE VELOCITY – particular point in onedistance travel by a wave second.per unit time , metres persecond (ms-1), v Unit for frequency, hertz (Hz), f
Different types of waves Radio Waves- longest wavelength. AM/FM, TV Microwaves- 2nd longest wavelength. Radar, Microwaves Infrared Waves- 3rd longest wavelength. Infrared photography, night vision Visible Light- 4th longest wavelength. Microscope, astronomy Ultraviolet Light- 5th longest wavelength. Sterilization X Rays- 6th longest wavelength. Medical exam of teeth and bones Gamma Rays- Shortest wavelength. Used in cancer treatment and food irradiation
Radio Waves Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radio waves do more than just bring music to your radio. They also carry signals for your television and cellular phones.
Radio Waves Objects in space, such as planets and comets, giant clouds of gas and dust, and stars and galaxies, emit light at many different wavelengths. Some of the light they emit has very large wavelengths - sometimes as long as a mile! These long waves are in the radio region of the electromagnetic spectrum.
Speed of Electromagnetic Waves All electromagnetic waves move at the speed of light Remember… Speed= wavelength x frequency Only the wavelength and frequency change This change decides which type of electromagnetic wave it is (radio, gamma, etc.)
Speed of Light The speed of light in a vacuum= 2.99792458 x 108 m/s The speed of light in air= 2.99709 x 108 m/s We use 3 x 108 m/s which equates to 300 million meters per second!