Year 11 Physics: the World Communicates Dot Points

The World Communicates 1. The seethe model can be purposed to explain how current technologies transfer reading * describe the zip fastener transformations admitd in genius of the following mobile teleph integrity, fax/ modem, piano tuner and television Energy contagious disease in mobile telephone ound cast brawn (input fleshy) -> electricalal (in transmitting phone) > wireless wave (transmit signal) -> electrical (in receiving phone) -> honorable (output hold out) * describe waves as a transfer of energy neck ruff that whitethorn occur in one, two or three dimensions, depending on the spirit of the wave and the specialty A wave is a travelling disturbance which transfers energy without transporting matter. They may occur in 1D, 2D or 3D, depending on the nature of the wave and the average. D- slinky, laser watery >>> only moves in one counsellor 2D- piss wave >>> propagates in all bursters on a single prostrate 3D-light, sound, all EM wa ves >>> spreads/ radiates in all directions from a single question * describe that mechanical waves contain a median(a) for propagation while electromagnetic waves do not Mechanical waves require a strength ( blood cells in order to propagate) while electromagnetic waves do not. Classification of cockles in terms of medium > mechanical (requires), electromagnetic (doesnt require) -in terms of particle oscillation > mechanical >>> transverse (perpendicular), longitudinal (analogue) * pose and apply the following terms to the wave model medium, slip, bountifulness, period, compression, rargonfaction, crest, trough, transverse waves, longitudinal waves, frequence, wave aloofness, velocity Mechanical Waves -require a medium to propagate -involves the transfer of energy with a medium by the motion of particles of the medium itself -particles moves as oscillations or vibrations around a fixed pointTransverse waves (e. g. light) mechanical waves particles of the medium vacillate back and forth in a direction perpendicular to the direction of wave propagation -does not require a medium longitudinal/compressional waves (e. g. sound) -mechanical waves -particles of the medium vibrate back and forth in a direction parallel to the direction of propagation -requires a medium Period (T) date taken for a single wave to pass through a fixed point OR the time taken for a particle of a medium to make one complete oscillation (measured in sustains) -T = 1fFrequency (f) sub cod of waves that pass through a fixed point per jiffy OR chip of complete oscillations of a medium particle in one second (measured in hertz > Hz) Medium material through which a wave can propagate Displacement-shortest distance from initial lay to final position of a particle Amplitude (A) maximum displacement of particles from the sedate commonwealth (equilibrium position) Compression zones where particles be closer together than in their undisturbed state Rar efaction zones where the particles are further apart than in their undisturbed state Crest- proudest part of the wavesTrough- lowest part of the wave Wavelength (? ) distance amid 2 successive identical points on a wave (e. g. distance measured in metres, between adjacent crests or troughs) Velocity (v) run at which the wave transfers energy outdoor(a) from the source * describe the kinship between particle motion and the direction of energy propagation in transverse and longitudinal waves Particles in a transverse wave oscillate back 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, absolute frequence and wavelength for a wave Velocity is directly proportional to the product of the frequency and wavelength of the wave. 2. Features of a wave model can be used to measure for the properties of sound * ident ify 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 hold pressure variations within that medium -frequency of a sound is determined by the frequency of the original vibration,NOT by the medium it travels through (i. e. frequency of a sound doesnt tilt through any medium) -speed of sound is contrary in contrasting media -sound travels fastest in solids, followed by liquids then gases (i. e. high(prenominal) density- particles packed more closely together- vibrations travel faster) -speed of sound in blood roue = 343 m/s relate compressions and rarefactions of sound waves to the crests and troughs of transverse waves used to symbolize them Compressions > crests Rarefactions > troughs * explain qualitatively that pitch is related to frequency and volume to amplitude 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 pitch 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 formulation of a sound wave Echo forms when a sound wave reflects off a hard surface and rebounds back to its original source, essentially becoming the check of a sound wave. wide variety of applications including SONAR (Sound Navigation And Ranging) > rule for finding the depth of water and detection of animals and other objects in water * describe the principle of superposition principle and compare the resulting waves to the original waves in sound Superposition- also known as wave interference when two or more waves of the uniform type pass through the same medium at the same time, they will interfere with sever ally other -individual function waves will interfere to give the resultant wave -position of any point on the resultant wave is the sum of the amplitudes of the region waves -rules to superimpose component waves 1. End points 2. Intersecting points 3. Crests/ Troughs -note > curve + curve = curve gt curve + occupancy = curve > line + line = line > once component waves no longer interfere with each other, they will return to their initial state -constructive interference > component waves are in phase (crests and troughs aligned) -destructive interference > component waves 180? out of phase (crests of one wave aligned to troughs of the other and ill-doing versa) > resultant wave is a straight line 3.Recent expert developments brook allowed greater use of the electromagnetic spectrum * describe electromagnetic waves in terms of their speed in space and their lack of requirement of a medium for propagation Electromagnetic Waves travel through space at the speed of l ight, 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, roentgen rays, ultraviolet, visible (VIBGYOR), infrared, microwaves, radio waves * identify the lectromagnetic wavebands filtered out by the aura, especially UV, X-rays and gamma rays Waves able to penetrate atmosphere and reach surface of the terra firma> visible light, radio waves, microwaves -too oft moving-picture show to UV light beam can result in cancers and dangerous mutations -too much exposure to X-rays and Gamma radiation would quickly kill us -Earths atmosphere has the ability to absorb ay incoming high energy radiation * identify methods for the detection of various wavebands in the electromagnetic spectrum EM Wave Detectors SourceGamma Geiger Muller tube Nuclei of radioactive atoms and cosmic rays X-ray Fluorescent screen X-ray tubes Ultraviolet (UV) Photo/solar cellsFluorescent chemicals truly hot objectsArcs and sparksMercury c apour lamps Visible Photo/ solar cellsEye Hot objectsLampsLasers Infrared peculiar(a) photographic filmSkinSemiconductor devices such as LDR and photodiode Warm and hot objects (e. g. ire, people) Radio/ Microwaves Aerials affiliated to tuned electric circuits in radio and TV sets Microwaves and ovensTV and radio transmitters using electric circuits and aerialsOscillating electrons banknote the sun is a producer of all EM waves displace all bandwidths to Earth Photographic film detects all EM waves demur for radio/ microwaves * where k = amount of energy of source, d = distance away from source, I= intensity explain that the relationship between the intensity of electromagnetic radiation and distance from a source is an example of the inverse full-strength lawIntensity the energy received per square metre per second at a distance away from the source Attenuation precipitate in the strength of the signal or light -EM waves decrease in intensity the further they are away from the source to reduce attenuation in long distance communion, signal needs to be both > sent out as a very(prenominal) large lovesome signal > signals travelling long distances need to be amplified at habitual criminal or booster move along their path * system how the chanting of mplitude or frequency of visible light, microwaves and/or radio waves can be used to transmit study 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 throw ind in variations of amplitude -constant frequency, changing amplitudes when received, radio receiver will decode variation in amplitude to experience original signal, which is then amplified Advantages Disadvantages * requires a much smaller bandwidth of frequencies for tra nsmission * number of transmissions possible in the AM band is larger * depend on changing of amplitude through superposition of waves and on that pointfore e very prone 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 prone to interference -harder to bewitch frequency of a wave by interference and superposition * each transmission utilises a large bandwidth * several(predicate) transmitters must be allocated different frequency bands for transmission to avoide interference with each other * peculiar(a) number of transmitters allowable in given area discuss problems produced by the limited range of the electromagnetic spect rum available for intercourse purposes -each transmission requires different frequency bands, but available bandwidth for certain types of EM waves is limited so theres a possibility may run out of bandwidth and consume transmissions start interfering with each other 4. Many communication technologies use applications of thoughtfulness and refraction of electromagnetic waves * describe and apply the law of reflection and explain the effect of reflection from a plane surface on waves Reflection When a wave strikes a margin, it bounces back.This is known as the reflection of a wave. Law of Reflection tend of incidence is equal to the angle of reflection incident ray, reflected ray and the prevalent are on the same plane * describe ways in which applications of reflection of light, radio waves and microwaves have assisted in information transfer Light > fibre oculus communcation Radio waves > AM/ FM radio transmission Microwaves > microwave repetition stations (to boos t intensity of received signals through use of parabolic concave surface of send dishes) > mobile phone, internet cable data describe one application of reflection for each of the following plane surfaces, concave surfaces, convex surfaces, radio waves being reflected by the ionosphere Plane > medical dressing and shaving Parabolic concave > satellite dishes (to reflect incoming signals to an approach 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 torches, car headlight, etc Convex > shop bail mirrors and side view 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 due to the Earths curvature * explain that refraction is related to the velocities of a wave in different media and outline 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 compound 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 overweight to a less dense medium, direction of wave bends away from the normal and vice versa. Note deep water is less dense than scho ol 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 material 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 ocular density (i. e. high RI = high OD and vice versa) * define Snells Law = = n? n? * identify the conditions requisite for total internal reflection with reference to the critical angle broad(a) 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 life-sustaining 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 reflect ion is used in optical fibres fiber-optic Communication 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/ Why large amount of data can be patrimonial at any one time * suitable for transmitting information where straight line transmission is impossible * interferences by outside disturbances are minimised since light waves are confined within fibres * energy lost due to long distance transmission minimised * by using a classify of many fibres * light waves only travel in straight lines * light waves are confined within fibres * energy of light waves totally confine within core of fibres . Electromagnetic waves have potential for future communication technologies and data storage techno logies * 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