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Transcription

1 Ph~ sics 2220 Sp.'ing 2UI3.John llefonl...~ I Name: Unid: Discussion TA: 1 A conducting rod oflength t = 35.0 cm is free to slide on two parallel conducting bars as shown. Two resistors, RJ = 2.00 nand R2 = 5.00 n are connected across the ends ofthe bars to form a loop. A constant magnetic field B =2.50 T is directed perpendicularly into the page. An external agent pulls the rod to the left with a constant speed of v = 8.00 mls.. [8pts.) Find the currents in both resistors. [6pts.} Calculate the total power delivered to the resistance ofthe circuit. [6pts.} Find the magnitude ofthe applied force that is needed to move the rod with this constant velocity. b) r::: ~ +-?2.. -,; J,'L f!., -+ r.:: 1 -::. ($. t; '3- (2-) +- ( I. L(f ( ') ) r;-~3f'~-v3j () r -- f. V r:: p y -- ::...-:- 3 Lf 3 &' [F~ Lf { 2"1 N

2 Physics 2220 Spi-ing 2013.John HcFonJ Nrune: Unid: Discussion TA: [20 pis.] A piece ofcopper wire with thin insulation, 200 m long and 1.00mm in diameter, is wound onto a plastic tube to form a long solenoid. This coil has a circular cross section and consists oftightly wound turns in one layer. Ifthe current in the solenoid drops linearly from 1.80 A to zero in seconds, an emf of 80.0 m V is induced in the coil. What is the length ofthe solenoid, measured along its axis? Assume the radius ofsolenoid is much greater than 1.00 mm. t::r:::- {, ~A.6t-; () S -3 :: ' OxIO V. [.).t _ L.- AI tj2 A)l.o ht. -. bt 2 li?(4',ix((i) ~ ~oo. ~ ~LL_::_O-.-7-~--:= ~ 0 r (go>lio-j) ( )

3 Ph~ sics 222U Spring 20]3.John DeFord._ J Name: Unid: Discussion T A: Consider a series RLC circuit having the following circuit parameters: R = 200 n, L = 663 mh, and C = 26.5 J.LF. The applied voltage has an amplitude of 50.0 V and a frequency of 60.0 Hz. [5 pts.] Find the current I max, including its phase constant <II relative to the applied voltage b.v. [5 pts.] Find the voltage b.vr across the resistor and its phase relative the current. [5 pts.] Find the voltage b.v c across the capacitor and its phase relative to the current. [5 pts.] Find the voltage b.v L across the inductor and its phase relative to the current. V-> = ::z.1i-t -::;..l-1\ '0 =: s7~. 11 ('.c..ys XL-::: ~ L :;; (--S7b.,,){(,t 1 x 1o J ) -:::: 2J.{'7 <=tj A X -...L _ -1 _(.::: tott); /2. A c.. - tj->c - 37'.'" ;2..1.$")t\O ~ (;.I~'i, J:--f! d~ CA- Q~ lit. '/2- =l".[t+ (~"-~o)]. 'I>. ~ ~ [ 2.<)0' f. ( 7 tf"!. 1->~ lop. Il) ] (~,-~qf(: ~::;: 2 if1. er I A ~~ 1~/( xq) f) -:: -t~' (2! f;~()()' Jt) I~~

4 Ph)'sics 2220 S. ')0) 1 J' D F d Name: Unid: ~ Discussion TA: 4 Sbow all work! An 80.0 n resistor, a 200 mh inductor, and a J.1.F' capacitor are connected in parallel across a 120 V (nns) source operating at 374 radls. ~ [5 pts.] What is the resonant frequency ofthe circuit? [6 pts.] Calculate the nns current in the resistor, inductor and capacitor. [5 pts.} What is the nns current delivered by the source? [4 pts.] Is the current leading or lagging behind the voltage? By what angle? XL. ':". ()J L ;:; 37'1 ('200)('\'0 1 ) ~ 7/f 'go fl, ); 11 ~.J- _ ~~ 17,g25".Sf. I ~1 ~ Cj Xc. ~ ",e. - J1'f {.IS)(.0 ).J- - ~-1.)7'1' '"') UJ. =- [ L Col'h -[(ZtDJ< i6~ ( o.,,~)() ~ b) :r~ ='.. '" ~ '" 8J 1(. ~ 0 tl.. ~ ~ ~ ~ ::- f]i!j >< L,.. 71("" '2 (), ) 2-~ :::: 10' /17!J 1. c. -:: ~ - J!';..:. 'l..e.,i g253 \ I S, 773. r:;o ra..!/s I

5 Ph~sics 2220 Sp.'ing 20L Name: Vnid: Discussion TA: A microwave source produces pulses of20.0 GHz radiation, with each pulse lasting 1.00 ns. A parabolic reflector with a face area of radius~ is used to focus the microwaves into a parallel beam ofradiation, as shown in the drawing. The average power during each pulse is 25.0 kw em (e) [4pIS.] What is the wavelength ofthese microwaves? [4pIS.} What is the total energy contained in each pulse? [4pIS.} Calculate the average energy density inside each pulse. [4pIS.} Determine the amplitude ofthe electric and magnetic fields in these microwaves. [4pIS.} Assuming this pulsed beam strikes an absorbing surface, calculate the force exerted on the surface during the 1.00 ns duration ofeach pulse. fa) ). -:: S- -::- ~ ~ro.ol~ J t :;?ox,ql b) t f)~ t e V\ if1 ~ :::: (? <) x I if f) ( S.:::. f C. - 2 E' c)<() -~ Z- '2.. z 7rJ ~ f- Ifel 2C}Jo 2.