foreign [Music] candidates should be able to know the main region of the electromagnetic spectrum in order of frequency and in order of wavelength know that all electromagnetic waves travel at the same speed in vacuum describe typical uses and the harmful effects of the different region of the electromagnetic spectrum know that many important system of communications rely on electromagnetic spectrum including artificial satellites mobile phone wireless Bluetooth and Optical fibers know the difference between a digital and analog signal and sound can be transmitted as a digital or analog signal explain the benefits of digital electromagnetic spectrum all electromagnetic waves have the following properties they are all transverse waves they can all travel through a vacuum they all travel at the same speed in a vacuum its speed in a vacuum is three times ten to the power of 8 meters per second and is approximately the same in air the electromagnetic spectrum is arranged in a specific order based on the wavelengths or frequencies the main groupings of the continuous electromagnetic spectrum are radio waves microwaves infrared visible light red orange yellow green blue indigo violet ultraviolet x-rays gamma rays this order is shown in the diagram from longest wavelength to shortest wavelength lowest frequency to highest frequency lowest energy to highest energy size of wavelength of radio wave is approximately to the size of the building microwave is approximately to the size of baseball infrared is approximately to the size of pinpoint visible light is approximately to size of the bacterial ultraviolet is approximately to size of virus x-rays is approximately to size of atom gamma rays is approximately to size of subatomic particles the higher the frequency the higher the energy of the electromagnetic waves electromagnetic wave with higher energy is highly ionizing harmful to cells and tissues causing cancer such as UV X-rays and gamma rays electromagnetic wave with lower energy is less ionizing less harmful to humans such as radio waves microwaves infrared and visible light useful for communications uses of electromagnetic waves electromagnetic waves have a variety of uses and applications radio waves communication radio waves are used to transmit the signal of radio and television they are also used in cellular networks GPS and Wi-Fi radio frequency identification or RFID RFID tags use radio waves to identify people or objects they are used in a variety of applications such as inventory tracking access control and payment systems Bluetooth is used to communicate between two Bluetooth compatible devices astronomy radio telescopes are used to observe the naturally occurring radio waves that come from stars planets galaxies and other astronomical objects microwaves communication microwaves are used to transmit the signal of satellites television and mobile phones they are also used in radar systems cooking microwaves are used to heat food in microwave ovens they work by causing the water molecules in food to vibrate which creates Heat infrared is emitted by warm objects electric grills some electric grills use infrared heat to cook food remote controls remote controls use infrared light to send signals to devices such as TV Intruder alarms are the motion sensor thermal imaging infrared cameras can be used to create images of objects that emit infrared radiation this can be used for medical imaging security and Industrial applications Optical fibers Optical fibers are used to transmit the signal in the communication which is more efficiently than visible light visible light seeing visible light is the part of the electromagnetic spectrum that can be detected by the human eye it is used for vision photography and videography communication visible light can be used to transmit data in Optical fibers ultraviolet fluorescence some substances glow when they are exposed to ultraviolet light this can be used to create security markings and detect fake banknotes tanning ultraviolet light from the sun can cause tanning it can also cause skin cancer sterilization ultraviolet light can be used to sterilize surfaces and kill bacteria it is used in hospitals Laboratories and food processing plants x-rays Medical Imaging x-rays are used to create images of the inside of the body they are used to diagnose diseases and injuries security scanning x-rays are used to scan luggage and people at airports and other security checkpoints gamma rays sterilizing food and medical equipment gamma rays can be used to bacteria and living things cancer treatment gamma rays are used to kill cancer cells harmful effects of electromagnetic waves on people the higher the frequency of an electromagnetic wave the higher its energy electromagnetic wave with higher energy is more ionizing meaning that it can remove electrons from atoms or molecules this can be harmful to cells and tissues and can even cause cancer electromagnetic wave with lower energy is less ionizing and is less harmful to humans it can still be harmful however if it is absorbed in large amounts beyond the visible part of the spectrum the energy becomes large enough to ionize atoms the main risks associated with electromagnetic waves are summarized as radio waves no known Danger microwave possible heat damage to internal organs when the water molecules in the body absorb microwave strongly infrared inframed can cause heating effects in tissues meaning it can also cause skin burns but it is less likely to cause internal damage than microwaves visible light very bright light can cause eye damage this is because the retina of the eye is sensitive to light ultraviolet if eyes are exposed to high levels of UV it can cause severe eye damage skin cancer ultraviolet is ionizing meaning it can kill cells or cause them to malfunction resulting in premature aging and diseases such as skin cancer x-rays x-rays are the most ionizing radiation meaning they are able to penetrate the body and cause internal damage so they are caused to kill cells mutation of genes and cancer gamma rays the harmful effects of gamma rays like as x-rays because they are the most ionizing radiation so they are caused to kill cells mutation of genes and cancer it is important to note that the harmful effects of electromagnetic waves depend on the amount of radiation that is absorbed a small amount of radiation may not be harmful but a large amount of radiation can be very harmful the risk of harm also depends on the type of tissue that is exposed to the radiation for example the retina of the eye is more sensitive to light than other tissues so it is more likely to be damaged by exposure to visible light the best way to protect yourself from the harmful effects of electromagnetic waves is to limit your exposure this means avoiding using electronic devices for long periods of time staying away from sources of strong radiation and wearing protective clothing when necessary Communications with satellites geostationary and polar orbiting satellites are both used for communication geostationary satellites orbit above the earth's equator the orbit of the satellite is 24 hours at a height of 36 000 kilometers above the Earth's surface much higher than polar satellites used for radio and telecommunication broadcasting around the world due to its high orbit polar or low orbit satellites orbit around the Earth's North and South Poles these orbit much lower than geostationary satellites at around 200 kilometers above sea level used for monitoring the weather military applications and taking images of the Earth's surface there is a much shorter time delay for signals compared to geostationary orbit signals the signals and images are much clearer due to the lower orbit however there is limited use in any one orbit because more than one satellite is required for continuous operation system of communications many important systems of communications rely on Long wavelength electromagnetic radiation including Bluetooth use radio waves to transmit information between electronic devices over short distances such as phones and speakers this is because radio waves pass through walls but the signal is weakened on doing so mobile phones and wireless internet use microwaves because microwaves can penetrate some walls and only require a short aerial for transmission and reception Optical fibers are used for cable television and high-speed Broadband because glass is transparent to visible light and some infrared visible light and short wavelength infrared can carry High rates of data digital and analog signal analog signals vary continuously they can take any value examples of analog technology include telephone transmission and some broadcasting a digital signal can only take one of two discrete States these are usually referred to as one and zero high and low or on and off the key advantages of transmission of data in digital form compared to analog r the signal can be regenerated so there is minimal noise due to Accurate signal regeneration the range of digital signals is larger than the range of analog signals they can cover larger distances digital signals enable an increased rate of transmission of data compared to analog extra data can be added so that the signal can be checked for errors sound waves that can be transmitted as a digital or analog signal signals for speech or music are made up of varying frequencies in order to make out the information clearly the signal needs to be transmitted with as little interference as possible the signal goes is converted both before transmission and after being received before transmission the signal is converted from analog to digital after being received the signal is converted from digital to analog I hope you found this video helpful if you did I would be grateful if you would subscribe to my channel share this video with your friends and leave a positive comment your support will help me to continue making videos and encourage me to create new content thank you