2000 Exam 2 & Key

2000 Exam 2& - 21.01 KEY 1 A computer operates at 110 V and 3.25 A If the cost of electrical energy is $0.09 kW—h determine the cost to leave

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Unformatted text preview: 21.01. .- KEY 1. A computer operates at 110 V and 3.25 A. If the cost of electrical energy is $0.09 / kW—h, determine the cost to leave this computer on for 18 a day for 6 days. a. $5.25 b. $12.42 2. A cylindrical wire of uniform radius of 1.5 cm carries a current of 2.5 A produced by an electric field of 180 V/m directed parallel to the Wire’s axis. Determine the ‘ resistivity of the material of which the wire is made. 0.0181 Q—m 0.0950 Q-m 0.4529411 d 0.264 mm 0.051 Q—m 3. In the circuit shown in the figure, determine the current in the 30 £2 resistor. Assume that the battery has no internal resistance. ‘ ' 7.» 99‘s? ‘ 0.342 A 0.289 A 0.227 A . 0.496 A © 0.129 A 15:2 20V 949.0%» 3052 4. In the circuit shown, the capacitor is initially uncharged and the switch is open. At tlme t = O, the switch is closed. At what time t > 0 will the current in the resistor have decayed to 6.0 11A? The battery generates an emf of 12 V with no internal resistance, R = 300 k9, and C= 60 HF. a. 11.5 s . (E 34.1 s ‘ R C. S 6 d. 64.4s e. 99.83 006 210] KEY 5. In the circuit shown in the figure, determine the magnitude of the current in R3. Both _ batteries generate an emf of 9.0 V and have no internal resistance; R1 = 10 Q, R2 =60 Q, andR3 =20 Q. a. 0.915 A b. 0.761 A @ 0.585 A d. 0.459 A e. 0.241 A M 6. A particle of unknown charge of magnitude q, unknown mass m and velocity v = (4.8 x 106 m/s) i enters a region of constant magnetic field B = (0.5 T) j. The particle is initially deflected in the negative z—direction and follows a semicircular path of radius r = 0.1 m. What is the sign of the particle’s charge and what is its > charge—to-rnass ratio q/m? 7. A wire coil of area A = 60 cm2 with n = 100 turns experiences a maximum torque of 18.0 N-‘mwhen placed in a uniform magnetic field of 2.0 T. What is the current through the coil? ‘ 8. A very long, thin wire is bent in a plane as shown in the figure such that the middle of the wire forms three—quarters of a loop of radius r = 0.15 m ( where r is much less than the length of the wire). If a current I = 2.0 A flows through the wire, determine the magnitude and direction of the magnetic field at point P at the center of the loop in the wire. . E‘BFISMO‘bT ‘m‘10 130% 9. uniform current of constant current density of magnitude J = 3.0 A/m2 flows in a long conducting cylindrical tube in the direction parallel to its axis. The inner radius of the tube is r1 = 5 cm, and the outer radius is r; = 6 cm. Find the magnetic field at a d1stance r from the tube’s axis for: a) r < r; and b) r > r2. 10. Two long, parallel wires are separated by a distance d = 0.3 m and carry currents of 11 = 0.2 A and [2 = 0.3 A flowing in opposite directions. Calculate the magnitude of the force exerted by each wire on a 2.0-meter—long section of the other wire. Is this force attractive or repulsive? n. ‘EZI ‘ 8.0X10‘8N ' YC Puluvc C ‘l ; 1c W mum 4,3 3.3 e l s M13033“ 1 1:15.011 0 r‘v. 2. 0‘! 1: IO'gTr-J‘s r . V>V'z { 4‘ ZZZO‘EXam 2 " KEY l Syr’ma 2000 L 73': V1 (WWW) E 5 PM: (Grimm) II V is 'm VoH’S Md 1 is ‘m umpires, Fax/Mt 65%";{E +0 0(de C: w.“ - At =6‘hom/dma '490‘4435) (Don? F0ng +0 Cngort r “to mdcrs) “E; M 1%; CW ‘Hrmugk 125 “math nah/ark +0 1;, +0 16min cw Warm :2 8, ml «m amide Imam arm: Hm? mix m was Par 0! m 3 mm" bramflw (Banksllfwwegfi. R. E a I = .‘g. m a» L121: 3 I ‘9' Avg“: I£.RB R33; .L .L ‘RI+RB -I = A R 5 RB R1+R3+RA M IRS 3A,? $IRS" RqRA 5. Kirchhoff; Mes. For 100111 3 E, '13. '13,, *Iszf‘o => 1. (73,442,) '* 12R; = a, 8 F0 2. . - 501V: £7 13 , r 100p ' 62‘12Rz +1.12: ' IZR‘s '0 “LR; + I;(R2+R3): Ea ~ '2; a. I. 12 IRWR; RI+R1 02 R ) g ‘ 4. 2 3. = z t I‘ I“ "R; E “MEL 72a ]= 3;... 6 . = :- 12[ Ra. Rf'Rz RI+RZ 1. 7R5:- (6‘ Ea ‘ $ Ia; stadium» = 5(2122m.) (R‘WWRM? Rfiuwkm) 4,. F=¢5xfi wem Gus mt falls => axillfxrfi. M $ . , (19-4waWWWWEWW For MM cirudawmfim, lfl-‘ma, = my} => qy‘B: my; => q.» T ..... 1c; I, 22.25 Km! 2 8. Use. 1‘54 SWGJOSH’iW yrimifk “(0 final A; « T5951; “(in equivaJaed of .1: P bi + (rEP’ +. $1 Treafh'fwo hu. .3 m exfwdifiofi. '{n infiu? in m dhfedm. All Camoan WWW: gab/slim ‘Ih W a! "P (4mm fiW—W*W>. Tlu m MCI/M cmn‘ri‘owfe 1h eflyfivwa’l om Mme line (75m: ’—’-'9~),M m, bar MM“ 31 «(f/q M1 Am» a Mama (BM: 4—‘1 Qnr =3> “T33 mt» MM? ' . - __ 5162*“ 1‘01. dXSMQ Gum We Em and Bow, WM; 3m Salami lw- BVM ' 1%? “Fir; = :1}; L2”: A—n Here x=~acot0, dx= +acs¢36d19 .I x’m’ = 039568 A" Julw'ede MI 1‘ 1101’ $ ‘ = ___g__ em a a _ I = “A BM 4" $9 9“ 13:? (we). 2m ’5 gjliédg‘?_wl§ Vial "'4‘ 411 V‘ ' 4an 4m" 2W 2r Mar i7 and?“ a flag. ‘60 flu {Me's Ouch. a.) §B~d§ = 27mg = O baa—ow, M Guam/"is W19” T‘v‘: b) §B~d§ =2mr'B= [loIenJmul =,Uo'~T‘A W A :(maehmlw 4m) =7r(r:—r,‘) Tlu «Gabi Wrwes MW 1% CWW M ii: dmmm W}M9( ha flu. relaM—W-ma, I , -—5- A A A [O ‘0‘ «warez ”’ 11L ‘3. W B, = %' 0141‘ Mr yafle M‘ We 2 .._..____—._..L_~ é—qz FOrct ‘:5 re (Misha. ...
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This note was uploaded on 04/15/2008 for the course PHYS 2220 taught by Professor Littler during the Fall '00 term at North Texas.

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2000 Exam 2& - 21.01 KEY 1 A computer operates at 110 V and 3.25 A If the cost of electrical energy is $0.09 kW—h determine the cost to leave

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