Electromagnetic Waves | Grade 10 Science DepEd MELC Quarter 2 Module 1

[Music] hi there in this video we will learn about the nature of electromagnetic waves and how they are produced and transmitted [Music] as a review a magnetic field is created around a wire that conducts electric current when current flows coiled wire known as a solenoid it acts as a magnet a solenoid with a core of iron acts as a strong magnet it is called an electromagnet [Music] as the name electromagnetic waves suggest it is considered to be both electric and magnetic in nature in other words an electromagnetic wave contains an electric field and a magnetic field electric and magnetic fields are the regions through which the push or pool of charged particles and magnets is exerted charged particles and magnets can push or pull certain objects without even touching them electromagnetic waves are produced by a charge that changes its direction or speed electrons are charged particles that can produce electric and magnetic fields but in order to create the vibrating electric and magnetic fields electrons must move a charged particle such as an electron moves back and forth or vibrates a changing magnetic field produces an electric field and in the same manner a changing electric field produces magnetic field [Music] an electromagnetic wave is made up of an electric field and a magnetic field positioned at right angles to each other and to the direction of motion of the wave since these fields are located at the right angles to the direction of motion of the wave electromagnetic waves are considered as transverse waves this means that both electric and magnetic fields oscillate perpendicular to each other and to the direction of the propagating wave like other waves such as water waves and waves in a rope electromagnetic waves carry energy from one place to another but unlike other waves electromagnetic waves do not carry energy by causing matter to vibrate it is the electric and magnetic fields that vibrate this explains why electromagnetic waves can travel in a vacuum where there is no matter but it does not mean that electromagnetic waves cannot travel through medium they certainly can [Music] light for example can be transmitted with a medium as through the atmosphere or without a medium as through space sound on the other hand needs a medium to be transmitted electromagnetic waves travel in a vacuum at a speed of 3 times 10 raised to the 8th power meters per second or 300 million meters per second it is denoted as c the speed of light the speed is slightly slower in air glass and any other material to appreciate just how great this speed is consider this light from the sun travels 150 million kilometers to earth in about 8 minutes nothing known in the universe travels faster than the speed of light since all electromagnetic waves have the same speed which is equal to the speed of light this means that as the wavelength decreases the frequency of the wave increases and as the wavelength increases the frequency decreases the spectrum of wavelength is exactly opposite to the spectrum of frequency in other words wavelength and frequency are inversely proportional to each other electromagnetic waves are known to possess the following properties 1. they are produced by accelerated or oscillating charge two they do not require any material or medium for propagation and three they travel in free space at the speed of three times ten raised to the eighth power meters per second after years of rigorous studies and experiments the principles came about to explain the electromagnetic wave theory the history of electromagnetic wave theory begins with ancient measures to understand atmospheric electricity in particular lightning people then had little understanding of electricity and were unable to explain the phenomena scientific understanding about the nature of electricity grew throughout the 18th and 19th centuries through the work of researchers prominent scientists each made a significant contribution in resolving how electromagnetic waves behave james clerk maxwell an english scientist developed a scientific theory to better explain electromagnetic waves when maxwell used this field theory to assume that light was an electromagnetic wave and then correctly deduced the finite velocity of light it was a powerful logical argument for the existence of the electromagnetic force field he noticed that electrical fields and magnetic fields can couple together to form electromagnetic waves maxwell discovered that a changing magnetic field will induce a changing electric field and vice versa heinrich hertz a german physicist applied maxwell's theories to the production and reception of radio waves the unit of frequency of a radio wave one cycle per second is named hertz to honor his contribution he proved the existence of radio waves in the late 1880s he used two rods that served as a receiver and a spark gap as the receiving antony where the waves were picked up our corresponding spark would jump hertz showed in his experiments that these signals possessed all of the properties of electromagnetic waves michael faraday is probably best known for his discovery of electromagnetic induction his contributions to electrical engineering and electrochemistry or due to the fact that he was responsible for introducing the concept of field in physics to describe electromagnetic interaction are enough for him to be highly recognized but perhaps it is not so well known that he had also made fundamental contributions to the electromagnetic theory of light [Music] andre marie ampere made the revolutionary discovery that a wire carrying electric current can attract or repel another wire next to it that's also carrying electric current the attraction is magnetic but no magnets are necessary for the effect to be seen he went on to formulate ampere's law of electromagnetism and produced the best definition of electric current during his time lastly hans christian ersted a danish physicist and chemist discovered that the electric current in a wire can deflect a magnetized compass needle a phenomenon the importance of which was widely recognized and which inspired the development of the electromagnetic theory [Music] when experts compiled all the discoveries of these scientists these form the basic principles of the electromagnetic wave theory the principles are as follows first many natural phenomena exhibit wave-like behaviors all of them water waves earthquake waves and sound waves require a medium to propagate these are examples of mechanical waves second light can also be described as a wave a wave of changing electric and magnetic fields that propagate outward from their sources these waves however do not require a medium to propagate third they propagate at 300 million meters per second through a vacuum [Music] fourth electromagnetic waves are transverse waves in simpler terms the changing electric and magnetic fields oscillate perpendicular to each other and to the direction of the propagating waves these changing electric and magnetic fields generate each other through faraday's law of induction and ampere's law of electromagnetism these changing fields dissociate from the oscillating charge and propagate out into space at the speed of light and lastly when the oscillating charge accelerates the moving charge electric fields changed too [Music] now that we better understand what electromagnetic waves are you might be wondering how sunlight is different from x-rays if both are electromagnetic waves that travel at the same speed electromagnetic waves like all types of waves are described by their physical wave features amplitude wavelength and frequency these are the characteristics that can vary and thereby produce many different kinds of electromagnetic waves [Music] amplitude is the maximum field strength of the electric and magnetic fields an electromagnetic wave is arranged according to its frequency and wavelength the term frequency describes how many waves per second a wavelength produces on the other hand the wavelength measures the length of an individual wave in meters [Music] the electromagnetic waves are often arranged in the order of wavelength and frequency and what is known as the electromagnetic spectrum because all electromagnetic waves travel at the same speed if the frequency of a wave changes then the wavelength must change as well waves with the longest wavelengths have the lowest frequencies while waves with the shortest wavelengths have the highest frequencies the amount of energy carried by an electromagnetic wave increases with its frequency arranged according to increasing frequency the electromagnetic spectrum displaced the following waves radio waves microwaves infrared visible light ultraviolet rays x-rays and gamma rays at the high frequency and short wavelength end it is important to note that these waves do not have an exact dividing region [Music] the different types of electromagnetic waves are defined by the amount of energy carried by their photons photons are bundles of wave energy from among the electromagnetic waves gamma rays carry photons of high energies while radio waves own photons with the lowest energies when talking about wavelength properties radio waves can be likened to the size of a building while gamma rays are as small as the nuclei of an atom gamma rays x-rays and high ultraviolet rays are classified as ionizing radiation as their photons have enough energy to ionize atoms causing chemical reactions while radio waves microwaves infrared rays and visible light are classified as non-ionizing radiation all electromagnetic waves can travel through a medium but unlike other types of waves they can also travel in a vacuum or empty space they travel in a vacuum at a speed of 3 times 10 raised to the 8th power meters per second or 300 million meters per second it is denoted as c the speed of light the wave speed frequency and wavelength are related as shown in the following equation v equals lambda f where v is the wave speed expressed in meters per second the frequency f is expressed in hertz and the wavelength lambda is expressed in meters let's try this sample problem assuming that the waves propagate in a vacuum what is the frequency of radio waves with the wavelength of 20 meters the given values are wave speed which is equal to the speed of light which is 300 million meters per second or 3 times 10 raised to the 8th power meters per second this is a constant value wavelength is equal to 20 meters or 2 times 10 raised to the first power meters and we are going to look for the frequency to solve this sample problem we have the formula wave speed equals wavelength times frequency since we are looking for frequency we will derive the formula to frequency equals wave speed divided by wavelength now we are ready to solve the sample problem we substitute wave speed by 3 times 10 raised to the 8th power meters per second and substitute wavelength by two times ten raised to the first power meters now we can divide three by two and cancel common units such as meter the unit remaining is per second remember the unit for frequency is hertz which is also cycles per second we now have 1.5 times 10 raised to the 8 minus 1 power since we are dividing exponents the frequency of radio waves are 1.5 times 10 raised to the seventh power hertz now let's wrap things up a wave is a disturbance that transfers energy an electromagnetic wave comprises of an electric field and a magnetic field at right angles to each other and to the direction of the motion of the wave all electromagnetic waves travel at the same speed in a vacuum which is 3 times 10 raised to the 8th power meters per second the electromagnetic waves are often arranged in the order of wavelength and frequency in what is known as the electromagnetic spectrum frequency describes how many waves per second a wavelength produces while wavelength measures the length of individual wave in meters waves with the longest wavelengths have the lowest frequencies on the other hand waves with the shortest wavelengths have the highest frequencies that's all for now we will be discussing about practical applications of the different regions of electromagnetic waves in our next video so stay tuned see you on our next video and don't forget to keep your minds busy if you like this video please subscribe to our channel and hit the notification icon for more videos like this

Channel: The Learning Bees

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Keywords: The Learning Bees, Department of Education, DepEd, MELC-Based, Most Essential Learning Competencies, Science, MELC, Grade 10, Electromagnetic waves, Radio waves, Microwaves, Infrared, Visible light, ultraviolet, X-rays, Gamma rays, Magnetic field, Electromagnet experiment, Electromagnetic wave theory, wavelength, frequency, wave speed, Formula for frequency, Speed of light, Speed of electromagnetic waves, Mechanical Waves, Transverse waves, Electrons, Photons, Electromagnetic spectrum

Id: CQV8PWRBhDc

Length: 17min 29sec (1049 seconds)

Published: Wed Jan 06 2021