MTE2 Wed 26, at 5:30-7:00 pm Ch2103 and SH 180. Contents of MTE2. Study chapters (no 32.6, 32.10, no 32.8 forces between wires)

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MTE Wed 6, at 5:30-7:00 pm Ch03 and SH 80 Contents of MTE Wok of the electic foce and

s la DC Cicuits and Kichoff s las RC cicuits Loentz foce and motion of chage in a magnetic

:30-4:00pm Lab oom (Ch 354) 6:00-7:30pm Lab oom (Ch 354 ) Study chaptes 7-3 (no 36, 30, no 38

uantity () compass needle taces field lines and points toads N -field lines stat in N and go

-field lines - 3 Eath s A Magnet Electic s Magnetic ield Lines N geogaphic pole almost at

attacted toad the geogaphic N pole (S pole of the -field) Similaities Density gies stength Ao

1 MTE Wed 6, at 5:30-7:00 pm Ch03 and SH 80 Contents of MTE Wok of the electic foce and potential enegy Electic Potential and ield Capacitos and capacitance Cuent and esistance, Ohm s la DC Cicuits and Kichoff s las RC cicuits Loentz foce and motion of chage in a magnetic field iot and Saat No Ampee s la, No magnetic popeties of matte Altenate Eams ill be: Wed 6 :30-4:00pm Lab oom (Ch 354) 6:00-7:30pm Lab oom (Ch 354 ) Study chaptes 7-3 (no 36, 30, no 38 foces beteen ies) This eek Hono Lectue Magnetic ields Susan Nossal: Climate change A ecto uantity () compass needle taces field lines and points toads N -field lines stat in N and go to S they do not stat o stop (no magnetic monopoles Electic dipole Ion filings sho patten of -field lines - 3 Eath s A Magnet Electic s Magnetic ield Lines N geogaphic pole almost at magnetic S pole S geogaphic pole almost at magnetic N pole A the N pole of a compass needle is attacted toad the geogaphic N pole (S pole of the -field) Similaities Density gies stength Ao gies diection Leae +, Noth Ente -, South Diffeences Stat/Stop on electic chage No Magnetic Chage lines ae continuous +

Chaged paticle in a -field: Loentz foce The magnetic foce = " ecto coss poduct acts only a moing chaged paticle Units: N = C m/s Tesla Effect

pependicula to both field and elocity the chage sign must be accounted fo = sin " is zeo hen and ae paallel o antipaallel is a maimum hen and

displacement => the magnetic foce does not do ok The thee chages belo hae eual chage and speed, but ae taeling in diffeent diections in a

foce? ######## # # # # ## # # =0 A) ) C) 3 D) Same 3 = sin() 9 Mass spectomete and selecto Cycloton Motion " to and paticle path is a cicle of

2 Chaged paticle in a -field: Loentz foce The magnetic foce = " ecto coss poduct acts only a moing chaged paticle Units: N = C m/s Tesla Effect of unifom magnetic field Effect of unifom -field on chaged paticle If chaged paticle is not moing - no effect If paticle is moing: foce pependicula to both field and elocity the chage sign must be accounted fo = sin " is zeo hen and ae paallel o antipaallel is a maimum hen and ae pependicula 8 The magnetic foce NEVER does ok on the paticle Magnetic oce and Wok Quick Quiz Magnetic foce pependicula to the paticle displacement => the magnetic foce does not do ok The thee chages belo hae eual chage and speed, but ae taeling in diffeent diections in a unifom magnetic field field can alte diection of elocity, but not the speed o the kinetic enegy Which paticle epeiences the geatest magnetic foce? ######## # # # # ## # # =0 A) ) C) 3 D) Same 3 = sin() 9 Mass spectomete and selecto Cycloton Motion " to and paticle path is a cicle of adius R a = /R is the centipetal acceleation R depends on m,,, R In ho much time does the paticle complete an obit? = ma = R m # #m "=, T = peiod = T " = angula elocity =

Epeiment in Lab: motion of chages in -field ) Tun on electon gun m = "V ) Tun on magnetic field (Helmotz coils) 3) Measue electon chage/mass as a function of V, R and = m "V R = m = m "V m R e - %V

3 Epeiment in Lab: motion of chages in -field ) Tun on electon gun m = "V ) Tun on magnetic field (Helmotz coils) 3) Measue electon chage/mass as a function of V, R and = m "V R = m = m "V m R e - %V gun Magnetic oce on a Cuent oce on each chage oce on length ds of ie " " Ids d = Ids " = IL " m = "V R 3 4 Homopola moto Ids A homopola moto has a -field along the ais of otation and an electic cuent poduced by the battey that moes adially though the magnet The esulting Loentz foce in the tangential diection poduces a toue in the magnet, hich is fee to otate ith the attached sce The name homopola efes to the absence of polaity change = IL " 5 Toue on a cuent loop Conside cuent loop in magnetic field pependicula to the plane of the loop => Zeo net foce oce on top path cancels foce on bottom path ( = IL) i oce on ight path cancels foce on left path ( = IL) If plane of loop is not to -field, thee is a toue on the loop (foce couple as fo electic dipole in E-field) 6 Calculation of Toue Potential Enegy of Magnetic Dipole Suae loop has idth W and length L (into the sceen) The toue is gien by: " = # + # " = & % sin# ' ) ( = IL " # = ILsin = IAsin A = L = aea of loop magnetic dipole moment I diection: " to plane of the loop = A I accoding to RH ule (hands culs on cuent) Note: if loop consists of N tuns, = N A I 7 Wok must be done to change the oientation of a dipole (cuent loop) in the pesence of a magnetic field Define a potential enegy U coesponding to this ok (U=0 hen magnetic dipole moment othogonal to -field = euilibium position coesponding to ma toue)

Quick Quiz Supise Which configuation has the geatest potential enegy?

field aligns compass needle kind of magnetism due to pemanent magnets and cuents o the same?

cuent Ion filings align ith magnetic field lines Cuent loop as magnetic dipole A cuent loop is an

like magnets (since the opposite poles ae close) Magnetic field loops aound the cuent (Right hand ule)

cente of the loop: d = out of page I ds ds # u d = 0 I 4" Each element of cuent poduces a contibution

4 Quick Quiz Supise Which configuation has the geatest potential enegy? Electic cuent poduces magnetic field Cuent (flo of electic chages ) in ie poduces -field The magnetic field aligns compass needle kind of magnetism due to pemanent magnets and cuents o the same? Cuent &=0 & = &=0 U = - U=0 U = A) ) Magnetic field C) 89 Hans Chistian Oested Magnetic field fom a cuent Ion filings align ith magnetic field lines Cuent loop as magnetic dipole A cuent loop is an electomagnet: it behaes like a pemanent magnet To cuent loops ith cuent in the same diection attact like magnets (since the opposite poles ae close) Magnetic field loops aound the cuent (Right hand ule) ield fom a cicula loop iot-saat La o a single chage in motion u = o a ie ith cuent 0 # u 4" At the cente of the loop: d = out of page I ds ds # u d = 0 I 4" Each element of cuent poduces a contibution to the magnetic field pemeability of fee space = = 0 = 4 " #07 Tm / A = 57 #06 Tm / A 3 0 Idlsin # # = 90 o Idl % d = 0 4" R 4" R " Ids 0 0 I 4" R # dl 0 I I "R = 0 4" R R

5 Happy sping beak to all 5

Last time RC circuits. Exam 2 is Tuesday Oct. 27 5:30-7 pm, Birge 145. Magnetic force on charged particle. Magnetic force on electric charges

Last time RC circuits. Exam 2 is Tuesday Oct. 27 5:30-7 pm, Birge 145. Magnetic force on charged particle. Magnetic force on electric charges Eam is Tuesda Oct. 7 5:0-7 pm, ige 45 Last time RC cicuits Students w / scheduled academic conflict please sta afte class TODAY to aange altenate time. Coes: all mateial since eam ook sections: Chap 7,