P<em>AC=P</em>max</p><ul><li><p>ThisequationseemstorelatetopowerinanACcircuit,whereP{AC}mightrepresenttheaveragepowerandP{max}themaximumpower.</p></li></ul></li><li><p>\frac{VP}{VS} = \frac{NP}{NS},(Idealtransformer)</p><ul><li><p>Where:</p><ul><li><p>V_Pisthevoltageintheprimarycoil.</p></li><li><p>V_Sisthevoltageinthesecondarycoil.</p></li><li><p>N_Pisthenumberofturnsintheprimarycoil.</p></li><li><p>N_Sisthenumberofturnsinthesecondarycoil.</p></li></ul></li></ul></li></ul><h4id="7e77404f−e9f4−447f−959f−bb2e052220f1"data−toc−id="7e77404f−e9f4−447f−959f−bb2e052220f1"collapsed="false"seolevelmigrated="true">InterferenceandDiffraction</h4><h5id="7bdb3eea−d6bc−4b19−9f27−cc9006d370aa"data−toc−id="7bdb3eea−d6bc−4b19−9f27−cc9006d370aa"collapsed="false"seolevelmigrated="true">ConstructiveInterference</h5><ul><li><p>2d = m\lambda_{film},wherem = 0, 1, 2, …</p><ul><li><p>Occurswhentwowavesareeitherbothinvertedornoneareinverted.</p></li><li><p>disthethicknessofthefilm.</p></li><li><p>\lambda_{film}isthewavelengthoflightinthefilm.</p></li><li><p>misanintegerrepresentingtheorderoftheinterference.</p></li></ul></li></ul><h5id="05b98f2c−4193−4116−ac69−93032ba730ef"data−toc−id="05b98f2c−4193−4116−ac69−93032ba730ef"collapsed="false"seolevelmigrated="true">DestructiveInterference</h5><ul><li><p>2d = (m + \frac{1}{2})\lambda_{film},wherem = 0, 1, 2, …</p><ul><li><p>Occurswhenonewaveisinverted.</p></li></ul></li></ul><h5id="4a07d393−b5b8−47c3−bc4f−f8e0528048ae"data−toc−id="4a07d393−b5b8−47c3−bc4f−f8e0528048ae"collapsed="false"seolevelmigrated="true">Generalformulasforinterference</h5><ul><li><p>Whenthefilmisinavacuum:\lambda{film} = \lambda{vacuum}</p></li><li><p>Generalformulasforinterference(EitherbothwavesORnoneareinverted):</p><ul><li><p>2d = m\lambda_{film},wherem = 1, 2, 3, …</p></li><li><p>2d = (m + \frac{1}{2})\lambda_{film},wherem = 0, 1, 2, …</p></li></ul></li></ul><h4id="b2f59b5b−b77c−4e2d−bb58−591ee0787ac2"data−toc−id="b2f59b5b−b77c−4e2d−bb58−591ee0787ac2"collapsed="false"seolevelmigrated="true">Constants</h4><ul><li><p>Speedoflight:c = 3 \times 10^8 m/s</p></li><li><p>Accelerationduetogravity:g = 9.81 m/s^2</p></li></ul><divdata−type="horizontalRule"><hr></div><h4id="a448560e−9e3f−42fe−9df3−4e7649b6e13e"data−toc−id="a448560e−9e3f−42fe−9df3−4e7649b6e13e"collapsed="false"seolevelmigrated="true">RotatingCoilinMagneticField</h4><ul><li><p>Figure(a)showsacircularcoilimmersedinaregularmagneticfieldperpendiculartothecoil′ssurface.</p></li><li><p>Figure(b)showsthecoilbeingrotatedinthemagneticfield.</p></li><li><p>Question:WhathappenswhenthecoilisrotatedinthemagneticfieldfromthepositioninFigure(a)tothepositioninFigure(b)?</p></li></ul><h4id="d02820b2−8d7f−4c41−9317−5adaedbdbc95"data−toc−id="d02820b2−8d7f−4c41−9317−5adaedbdbc95"collapsed="false"seolevelmigrated="true">MagnetsandWire</h4><ul><li><p>Figure(1)showstwomagnetswiththenorthpole(N)ofthefirstmagnetfacingthesouthpole(S)ofthesecondmagnet.</p></li><li><p>Thelengthofeachmagnetisl = 20.0 cmandtheheightish = 6.00 cm.</p></li><li><p>AuniformmagneticfieldofstrengthB = 54 mTexistsbetweenthemagnets.</p></li><li><p>Atautwireconnectedtoamilli−ammeterismovedfromthelowerendofthemagnetstotheupperend,perpendiculartothemagneticfieldlines,inatimeperiodof\Delta t = 0.2 s(Figure2).</p></li></ul><h5id="5c2e6beb−4be7−4fac−b39a−b56ca8db5773"data−toc−id="5c2e6beb−4be7−4fac−b39a−b56ca8db5773"collapsed="false"seolevelmigrated="true">Calculations</h5><p>a)Theinducedelectromotiveforce(EMF)generatedinthewire.<br>b)Theinducedelectriccurrentpassinginmilli−ammeter,iftheelectricalresistanceofthecircuitis2.0 \Omega.</p><divdata−type="horizontalRule"><hr></div><h4id="489ad3ca−9848−4f56−bb4d−f3b1c43b7957"data−toc−id="489ad3ca−9848−4f56−bb4d−f3b1c43b7957"collapsed="false"seolevelmigrated="true">HairDryerandPotentialDifference</h4><p>A.Amanufacturedhairdryeruses10 Aat120 V.Ifthedryerisusedinanothercountrywherethepotentialdifferenceis240 V.</p><h5id="2ea54319−29df−454e−bc10−49b2224b8f0e"data−toc−id="2ea54319−29df−454e−bc10−49b2224b8f0e"collapsed="false"seolevelmigrated="true">Questions:</h5><p>a)Whattool/deviceenablesustouseahairdryer,whenmovingbetweentwocountrieswithdifferentpotentialdifferences(Voltagesources)?<br>b)Findtheratioofthenumberofturnsintheprimarycoiltothenumberofturnsinthesecondarycoil.<br>c)Findthevalueofcurrentthatthehairdryerdrawsfromthe240 Vline?</p><h4id="0d444a2e−2651−4e10−a254−5d5d0bf25e1b"data−toc−id="0d444a2e−2651−4e10−a254−5d5d0bf25e1b"collapsed="false"seolevelmigrated="true">Transformers</h4><p>B.Thetablecontainstherelationshipsbetweenpotentialdifference(V),current(I),andthenumberofwindingsintransformers(N)intheprimary(P)andsecondary(S)windings.</p><h5id="575eed58−7e34−4417−a0ba−24844c18f754"data−toc−id="575eed58−7e34−4417−a0ba−24844c18f754"collapsed="false"seolevelmigrated="true">Step−UpTransformer</h5><p>Studytheinequalitiesinthetableandshowtherelationshipsbetweenthequantitiesinthestep−uptransformerandthestep−downtransformer,byplacingthemathematicalsymbols(>, <, =)correctly.</p><h5id="ca3ad526−d1cf−419f−ab3b−bd32e19f45e6"data−toc−id="ca3ad526−d1cf−419f−ab3b−bd32e19f45e6"collapsed="false"seolevelmigrated="true">Step−DownTransformer</h5><h4id="1a3ac8bf−199e−489e−ad69−d6994222ca50"data−toc−id="1a3ac8bf−199e−489e−ad69−d6994222ca50"collapsed="false"seolevelmigrated="true">MagnetandCoil</h4><p>A.Thenorthpoleofamagnetapproachesacoil,andthemilli−ammeterindicatorconnectedtoitmoves.Thefigureshowsasideviewofthemagnetasitapproachesthecoil.</p><h5id="3594fb6b−45be−4657−823c−c3fb0210627e"data−toc−id="3594fb6b−45be−4657−823c−c3fb0210627e"collapsed="false"seolevelmigrated="true">Question</h5><p>Determinethedirectionoftheinducedelectriccurrentgeneratedinthecoil,andexplainhowyougottheanswer(statethelawyoureliedontodeterminethis).</p><h4id="daf7e7eb−eb99−4a8e−80f4−ec3342ebd8c0"data−toc−id="daf7e7eb−eb99−4a8e−80f4−ec3342ebd8c0"collapsed="false"seolevelmigrated="true">LightSourcesandDouble−SlitExperiment</h4><p>B.Aretwolightsources,onegreenandtheotherred,coherent,orincoherent?Explainyouranswer.</p><p>C.Atopviewofthedouble−slitinvestigationisshowninFigure.Thewavefrontsinterfereconstructivelyanddestructivelytoformapatternoflightanddarkbands.</p><h5id="8f79703b−33f9−4fcf−8968−f56ab3515ae6"data−toc−id="8f79703b−33f9−4fcf−8968−f56ab3515ae6"collapsed="false"seolevelmigrated="true">Questions</h5><ol><li><p>Determinethetypeofinterferenceineachofthetwofiguresshownbelow?Markthebandthatproducesadarkband.</p></li></ol><divdata−type="horizontalRule"><hr></div><h4id="18d43de4−5c8b−4a22−a1c9−487ec9ffdc56"data−toc−id="18d43de4−5c8b−4a22−a1c9−487ec9ffdc56"collapsed="false"seolevelmigrated="true">Young′sDouble−SlitExperiment</h4><p>A.Young′sdouble−slitexperimentcanbeusedtomeasurethewavelengthofagivenlight.Inthefigurebelow,theslitsare1.90 \times 10^{-5} mapart,ascreenisplaced0.60 maway,andthefirstorderbrightbandis2.11 \times 10^{-2} mfromthecentralbrightband.</p><h5id="e7a24560−59f3−49f1−9e8c−f7ba6f007367"data−toc−id="e7a24560−59f3−49f1−9e8c−f7ba6f007367"collapsed="false"seolevelmigrated="true">Questions</h5><p>a)Calculatethewavelengthofredlight.<br>b)Whathappenstotheintensityofthebrightbandsaswemoveawayfromthecentralband?<br>c)Whatwouldhappenifwhitelightwasusedinsteadofred?</p><h4id="48128e00−4828−403d−a51c−8d1c2d11989e"data−toc−id="48128e00−4828−403d−a51c−8d1c2d11989e"collapsed="false"seolevelmigrated="true">OilSlickandInterference</h4><p>B.Youobservecoloredringsonapuddleandconcludethattheremustbeanoilslickonthewater.Youlookdirectlydownthepuddleandseeayellowgreenregion(\lambda = 555 nm),If(n{oil} = 1.45)and(n{water} = 1.33).</p><h5id="9e876d3f−1790−4d5f−ad0e−69f4414560fe"data−toc−id="9e876d3f−1790−4d5f−ad0e−69f4414560fe"collapsed="false"seolevelmigrated="true">Questions</h5><p>a)Determineinthefollowingtable,whathappenstothewave(wavephase)whenitisreflectedfromeachofthetwosurfaces:(air−oil)and(oilwater),byplacingasign(\checkmark$$) in the appropriate box:
| Inversion | No inversion |
|---|
air-oil | | |
oil-water | | |
b) Find the minimum thickness of oil that could cause this color.