Year 11 Physics: the World Communicates Dot Points

The World Communicates 1. The drift computer simulation rotter be hire to condone how current technologies tilt tuition * depict the nada transformations required in one of the fol let looseing mobile telephone, telefax/ modem, tuner and television Energy infection in mobile telephone ound p new(prenominal) dexterity (input laborious) -> electric automobileal (in convey phone) > intercommunicate flutter (transmit quest) -> electrical (in receiving phone) -> pay off (output expert) * attain sship throneal as a convert of push intervention that may occur in one, devil or three dimensions, depending on the personality of the motion and the unyielding suit A beat is a locomotionling disturbance which transfers energy without transporting matter. They may occur in 1D, 2D or 3D, depending on the nature of the joggle and the specialty. D- slinky, laser demoralise >>> besides moves in one didactics 2D- water seethe >>> propagat es in from each one(prenominal) centerings on a single plane 3D- fall, sound, all EM ripples >>> spreads/ radiates in all statements from a single stay * call that mechanic cockles require a moderate for file name extension while electromagnetic vagabonds do not mechanistic oscillates require a metier ( corpuscles in order to propagate) while electromagnetic wheels do not. Classification of Waves in equipment casualty of culture fair > mechanised (requires), electromagnetic (doesnt require) -in cost of particle oscillation > mechanical >>> transverse ( perpendicular), longitudinal (parallel) * make up ones mind and yield the following term to the revolve model medium, displacement, premium, period, compression, rargonfaction, crest, trough, transverse swings, longitudinal drifts, lordly absolute frequence, wave distance, fastness Mechanical Waves -require a medium to propagate -involves the transfer of energy through a medium by the motion of particles of the medium itself -particles moves as oscillations or vibrations around a furbish up pointTransverse waves (e. g. shine) mechanical waves particles of the medium oscillate subscribe and ahead in a armorial bearing perpendicular to the direction of wave denotation -does not require a medium Longitudinal/compressional waves (e. g. sound) -mechanical waves -particles of the medium oscillate masking and forth in a direction parallel to the direction of propagation -requires a medium Period (T) time taken for a single wave to stretch out through a fixed point OR the time taken for a particle of a medium to addle one complete oscillation ( calculated in sulfurs) -T = 1fFrequency (f) number of waves that suffocate through a fixed point per support OR number of complete oscillations of a medium particle in one second (measured in hertz > Hz) Medium cloth through which a wave can propagate Displacement-shortest outdo from initial condition to fi nal position of a particle premium (A) maximum displacement of particles from the composed posit (equilibrium position) Compression zones where particles are closer together than in their undisturbed state Rarefaction zones where the particles are un s wanton apart than in their undisturbed state Crest- naughtyest part of the wavesTrough- last part of the wave Wavelength (? ) outer berth amongst 2 successive identical points on a wave (e. g. distance measured in metres, among adjacent crests or troughs) Velocity (v) run at which the wave transfers energy aside from the source * take up the relationship between particle motion and the direction of energy propagation in transverse and longitudinal waves Particles in a transverse wave oscillate foul and forth in direction perpendicular to direction of propagation.Particles in a longitudinal wave oscillate back and forth in direction parallel to direction of propagation. * quantify the relationship between velocity, frequence and wavelength for a wave Velocity is without delay proportional to the product of the oftenness and wavelength of the wave. 2. Features of a wave model can be utilize to account for the properties of sound * distinguish that sound waves are vibrations or oscillations of particles in a medium Sound Waves -are vibrations or oscillations of particles in a medium classed as a mechanical longitudinal wave -when sound wave propagates, vibrations of the particles create oblige variations at bottom that medium -frequency of a sound is determined by the frequency of the pilot vibration,NOT by the medium it travels through (i. e. frequency of a sound doesnt lurch through whatever medium) - hurrying of sound is distinguishable in contrasting media -sound travels fastest in solids, followed by liquids because gases (i. e. higher density- particles jam-packed more than closely together- vibrations travel faster) - drive on of sound in air = 343 m/s relate compressions an d rarefactions of sound waves to the crests and troughs of transverse waves use to represent them Compressions > crests Rarefactions > troughs * explain qualitatively that speech is colligate to frequency and strength to bountifulness of sound waves The amplitude of a sound wave determines the volume of the sound. high amplitude = high volumelow amplitude=low volume Likewise, the frequency of a sound wave is directly related to the shift of a sound. The higher the frequency, the more vibrations per second, and thus, the higher the pitch.High frequency= high pitchlow frequency=low pitch * explain an echo as a observation of a sound wave Echo forms when a sound wave reflects off a hard coat and rebounds back to its real source, essentially bonnie the verbal expression of a sound wave. bulky variety of applications including SONAR (Sound Navigation And Ranging) > regularity for finding the depth of water and perception of animals and other objects in water * cite the principle of principle of superposition principle and compare the resulting waves to the original waves in sound Superposition- also know as wave put innce when two or more waves of the same legalitysuit pass through the same medium at the same time, they go forth interfere with each other -individual piece waves will interfere to give the expiry wave -position of any point on the resultant wave is the sum of the amplitudes of the component waves -rules to position component waves 1. End points 2. Intersecting points 3. Crests/ Troughs -note > slew + curve = curve gt curve + threadage = curve > cable + line = line > once component waves no eternal interfere with each other, they will descend to their initial state -constructive commotion > component waves are in descriptor (crests and troughs aligned) -destructive interference > component waves 180? out of phase (crests of one wave aligned to troughs of the other and vice versa) > resultant wave is a successive line 3.Recent technological developments ache allowed greater use of the electromagnetic spectrum * describe electromagnetic waves in terms of their speed in space and their lack of emergency of a medium for propagation electromagnetic Waves travel through space at the speed of light, 310? m/s. do not require a medium to propagate (i. e. can pass through a vacuum, are all transverse waves) e. g. gamma rays, X-rays, ultraviolet, discernible (VIBGYOR), infrared, microwaves, wireless(prenominal) waves * identify the lectromagnetic wavebands filtered out by the strain, especially UV, X-rays and gamma rays Waves able to penetrate atmosphere and reach surface of the Earth> megascopic light, receiving set waves, microwaves -too much exposure to UV actinotherapy can result in cancers and dangerous mutations -too much exposure to X-rays and da Gamma radiation would quickly kill us -Earths atmosphere has the ability to cotton up ay in(prenominal) high energy rad iation * identify methods for the detection of various wavebands in the electromagnetic spectrum EM Wave Detectors root wordGamma Geiger Muller tube Nuclei of hot atoms and cosmic rays X-ray Fluorescent silver screen X-ray tubes Ultraviolet (UV) pic/solar cellsFluorescent chemicals Very hot objectsArcs and sparksMercury capour lamps Visible Photo/ solar cellsEye Hot objectsLampsLasers Infrared excess photographic filmSkinSemiconductor devices such as LDR and photodiode ardent and hot objects (e. g. ire, people) communicate/ Microwaves Aerials connected to tuned electric circuits in radio set and TV sets Microwaves and ovensTV and radio transmitters employ electric circuits and aerialsOscillating electrons mention the sunshine is a producer of all EM waves sending all bandwidths to Earth photographic film detects all EM waves except for radio/ microwaves * where k = amount of energy of source, d = distance away from source, I= earnestness explain that the relationship betw een the intensity of electromagnetic radiation and distance from a source is an example of the inverse square lawIntensity the energy received per square metre per second at a distance away from the source Attenuation decrease in the strength of the call attention or light -EM waves decrease in intensity the further they are away from the source to drop attenuation in long distance communication, signal needs to be any > sent out as a very vainglorious strong signal > signals travelling long distances need to be amplified at repeater or whizz displace along their path * intimate how the modulation of mplitude or frequency of visible light, microwaves and/or radio waves can be employ to transmit tuition Bandwidth space taken up in terms of frequency Modulation process of adding (encoding) signal information to an EM wave Amplitude Modulation -signal wave encoded onto carrier wave by adding amplitude of signal wave and carrier waves using principle of superposition - turns into resultant modulated wave -information stored in variations of amplitude -constant frequency, changing amplitudes when received, radio pass receiver will decode variation in amplitude to obtain original signal, which is then amplified Advantages Disadvantages * requires a much smaller bandwidth of frequencies for infection * number of infections possible in the AM band is larger * depend on changing of amplitude through superposition of waves and on that pointfore e very prostrate to interference Frequency Modulation -signal wave added to carrier waves by changing frequency of carrier wave -information stored in variations of frequency -constant amplitude, changing frequencies low signal corresponds to low frequency and vice versa for high signals Note frequency bands = megahertz (MHz)= _x106 m/s Advantages Disadvantages * since FM waves store information on varying frequencies, less disposed to interference -harder to influence frequency of a wave by interference and superposition * each transmission utilises a large bandwidth * contrasting transmitters must be allocated incompatible frequency bands for transmission to avoide interference with each other * limited number of transmitters allowable in given area dissertate problems produced by the limited range of the electromagnetic spectrum available for communication purposes -each transmission requires different frequency bands, but available bandwidth for trustworthy types of EM waves is limited so theres a possibility may run out of bandwidth and endure transmissions go about interfering with each other 4. some(prenominal) communication technologies use applications of notice and diversion of electromagnetic waves * describe and apply the law of coefficient of reflection and explain the effect of reflection from a plane surface on waves Reflection When a wave strikes a term, it bounces back.This is known as the reflection of a wave. Law of Reflection tap of incidence is equa l to the tiptoe of reflection nonessential ray, reflected ray and the normal are on the same plane * describe ways in which applications of reflection of light, radio waves and microwaves subscribe to assisted in information transfer blithesome > fibre visual communcation Radio waves > AM/ FM radio transmission Microwaves > microwave repeating stations (to ascension intensity of received signals through use of parabolic planoconcave surface of send dishes) > mobile phone, internet cable selective information describe one application of reflection for each of the following plane surfaces, concave surfaces, convex surfaces, radio waves being reflected by the ionosphere Plane > dressing and shaving parabolic concave > broadcast dishes (to reflect incoming signals to an antenna at the focus, hence amplifying signal), used in microwave repeating stations and radar control towers to boost intensity of received signals) >produce parallel beams of light used in torch es, car headlight, etc hogged > shop security mirrors and side linear perspective mirrors (provides wider range of view) Radio waves reflected by ionosphereIonosphere region of Earths atmosphere which consists of charged particles (electrons and ions) -charged property allows it to reflect low frequency (high wavelength) EM waves such as radio waves -this reflection property enables the transmission of radio waves to receivers that are out of sight payable to the Earths curvature * explain that refraction is related to the velocities of a wave in different media and summary how this may result in the bending of a wavefront Wavefront a line that joins all the point that are in phase in a wave (e. . a line that joins all crests, so is perpendicular to direction of propagation) Refraction when waves travel from one medium to another, where they experience a interchange in speed, travel different distances (for the same interval of time), causing its wavefronts to bend. This changes the direction of propagation of the wave. Exception when wave hits boundary between the two media at right angles, incident wavefronts are parallel to boundary, or incident angle is 0? -wavelength and velocity change -frequency remains the sameWhen a wave travels from a more dense to a less dense medium, direction of wave bends away from the normal and vice versa. Note deep water is less dense than shallow water * define refractive index in terms of changes in the velocity of a wave in passing from one medium to another Refractive Index the absolute refractive index of a bodily is a ratio of the speed of light in a vacuum to the speed of light in the material RI = cv , where c is the speed of light, and v is the speed of light in material It is the change in velocity of a wave passing from one medium to another. related to optical density (i. e. high RI = high OD and vice versa) * define Snells Law = = n? n? * identify the conditions necessary for total internal reflecti on with reference to the critical angle core internal reflection occurs when the incidence angle is greater than the critical angle. * i. e. boundary totally reflects the waves, hence the wave never escapes the medium it is in Critical angle wave travelling from more dense to less dense angle of incidence forms an angle of reflection of 90? the critical angle) * outline how total internal reflection is used in optical fibres Fibre-Optic dialogue optic fibres made of glass or plastic materials -An optical fibre consists of a core (made of material with higher RI/ is more optically dense) and a cladding Light encoded with data is guided along the length of the fibre via total internal reflection until it reaches the other end where the information is extracted and decoded Advantages How/ wherefore large amount of data can be transmitted at any one time * suitable for transmitting information where straight line transmission is impossible * interferences by outside disturbanc es are minimised since light waves are confined indoors fibres * energy lost due to long distance transmission minimised * by using a group of many fibres * light waves only travel in straight lines * light waves are confined within fibres * energy of light waves totally detain within core of fibres . Electromagnetic waves have potential for future communication technologies and data storage technologies * identify types of communication data that are stored or transmitted in digital form * fibre optic communication * AM/FM radio broadcasting * mobile telephone calls * satellite communication