physics notes 'N'

Rebekah’sPhysicsNotes CONTENTPAGE:1.formulaesheet-------------------------------------------------------------------------2-3 2.physicalquantities,unitsandmeasurements-----------------------------------4-9 3.kinematics----------------------------------------------------------------------------10-13 4.forceandpressure-----------------------------------------------------------------14-18 5.dynamics-----------------------------------------------------------------------------19-23 6.energy---------------------------------------------------------------------------------24-29 7.kineticparticlemodelofmatter-------------------------------------------------30-34 8.thermalprocesses-----------------------------------------------------------------35-41 9.generalwaveproperties----------------------------------------------------------42-44 10.electromagneticspectrum------------------------------------------------------45-47 11.electricchargeandcurrentofelectricity------------------------------------48-52 12.DCcircuits--------------------------------------------------------------------------53-54 13.practicalelectricity----------------------------------------------------------------55-60 14.radioactivity------------------------------------------------------------------------61-68 1

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CHAPTER1:PHYSICALQUANTITIES,UNITSANDMEASUREMENTSPrefixes:-Prefixesaremultiples/decimalsof10toconvenientlyexpressphysicalquantitiesthataretoobigortoosmallFactor Prefix symbolMultiple 10¹² Tera TMultiple 10 ⁹ Giga GMultiple 10 ⁶ Mega MMultiple 10³ Kilo kSubmultiple 10 ⁻ ¹ Deci dSubmultiple 10 ⁻ ² Centi cSubmultiple 10 ⁻ ³ Milli mSubmultiple 10 ⁻⁶ Micro µSubmultiple 10 ⁻⁹ Nano n Physicalquantities-physicalquantitiesisaquantitywhichcanbemeasuredwithameasuringinstrumentBasequantities SIunit UnitsymbolMass Kilogram KgTemperature Kelvin KLength Metre MCurrent Ampere ATime Second s 4

Measuringphysicalquantities:-lengthcanbemeasuredusingameterrulerandameasuringtapeDigital calipers-isusedtomeasuretheinternalandexternaldiameters,depthofanobjectaccurately.(0to15cm) Part FunctionInternaljaw MeasuringinternallengthofanobjectExternaljaw MeasuringexternallengthofanobjectTail MeasuringthedepthofanobjectLockingscrew ToensurethatthejawsdonotmoveapartDigitaldisplay Toshownumericvalue Digital Micrometer ScrewGauge-Usedtomeasureobjectsthataretoosmalltobemeasureusingthedigitalcaliper(0to2.5cm) 5

Parts FunctionAnvilandspindle UsedtomeasurethediameterofanobjectZerobutton UsedtoresetthedisplayedlengthbacktozeroDigitaldisplay UsedtoshowthenumericvalueRatchet ToadjustthespindlesothatitisincontactwiththeobjectMeasurestofollowtoensureaccuratereading:-ensurethatratchetisturneduntilspindleisincontactwithobject-objectisplacedinbetweenanvilandspindle-ensurethatobjectisheldtightlyinbetweenanvilandspindle-butnottootightasthismaycausedamagetotheobjectPrecisionofaninstrument:-thesmallestunitofaninstrumentcanmeasureisknownasitsprecisionInstrument MeasuringrangeMeasuringtape 0toseveralmetersMeterruler 0to1mDigitalcaliper 0to15cmDigitalmicroscrewgauge 0to2.5cmAvoidingerrorsofmeasurement:-Whenusingameterruler,oureyesshouldbepositionedsuchthatourlineofsightisperpendiculartotheruler-ifmeasurementerrorsareintroduced,itiscalledparallaxerrorsMeasurementoftime:Pendulum-usedtomeasuretime-consistsofabobattachedtotheendofthestringfixedattheotherendofthestring.-apendulummovesbackandforthatregularintervals-theperiodisthetimetakenforthependulumtocompleteoneoscillation 6

-oneoscillationiscompletedwhenapendulumcompletestoandfrommotion-theperiodofapendulumdependsonthelengthofthestring-humanreactiontimeisarandomerrorwhichisthesourceoftheerrorthataffectstheaccuracyofameasurement.-tominimizetherandomerrors,repeatthemeasurementseveraltimestoobtaintheaverageofthereadingsT(periodofthependulum)= 𝑡(𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 𝑓𝑜𝑟 𝑋 𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠)𝑋 𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠 Factorsthataffecttheperiodofpendulum:Theperiodisaffectedbythelengthofthependulum-thelengthofpendulumincreases,theperiodincreases-thelengthofpendulumdecreases,theperioddecreases-whentheperiodofthependulumincrease,thependulumswingsslowerandviceversaTheperiodofapendulumisnotaffectedby:-massofbob-amplitudeofoscillation(angleofoscillation) Scalar andVector-Scalarquantitiesarephysicalquantitiesthathaveonlymagnitudeandunit-Vectorquantitiesarephysicalquantitiesthathavemagnitude,directionandunitScalarquantity Speed,distance,energy,density,length,time,pressure,temperature,mass,power,work,electricalchargeVectorquantity Velocity,acceleration,displacement,force,weightDistance:-distanceisthetotallengthcoveredbyamovingobjectREGARDLESSofthedirection-distanceisascalarquantity.itisthetotallengthcoveredinajourneywithoutindicatingthedirectionofmotion-distancedoesnotspecifythedirectionofthemovingobject 7

Displacement:-displacementisthedistancemeasuredinastraightlineinaspecificdirection-itisthedistancetraveledbytheobjectbetweentheinitialpositiontothefinalpositionoftheobjectinastraightlineinastateddirection-displacementisavectorquantityasitindicatesbothmagnitudeandthedirectionofhowthelengthbetweenthepointaremeasured-thenegativeandpositivesignsareusedtodenotethedirectionofthemotioninoppositedirections. 8

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CHAPTER2:KINEMATICS-kinematicsdescribesthemotionofobjectwithoutconsideringtheforceactingonit-motionisachangeinposition.whenanobjectisinmotion,itchangesitsposition-physicalquantitieslikedistance,displacement,speed,velocityandaccelerationareusedtodescribethemotionofobjectsDifferencesbetweendistanceanddisplacementDistance DisplacementTotallengthtraveledamovingobject,irrespectiveofitsdirectionofmotion Theshortestdistance(straightline)betweentheinitialandfinalpositionsoftheobjectinagivendirectionAscalarquantity(hasmagnitudeonly) Avectorquantity(hasbothmagnitudeanddirection)Alwayspositiveorzerobutcannotbenegative Canbepositive,negativeorzero Speedandvelocity:-speedisthechangeofdistanceperunittimeORdistancetraveledperunittime.-uniformspeediswhentheobjectmovesatthesamespeedthroughoutitsjourney,it hasauniformspeedORconstantspeed-thismeansthattheobjectmovesatthesamedistanceineverysecondoreachhour-averagespeedisthetotaldistancetraveledpertotaltimetakenAveragespeed= 𝑡𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑒𝑑 𝑡𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 -velocityisthechangeofdisplacementperunittime-velocityisavectorquantity.itisaspeedinaspecificdirection-SIunitforvelocityism/s-theformulatodeterminethevelocityofanobject:v= 𝑑(𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡)𝑡𝑖𝑚𝑒(𝑠) 10