ES1F11 - .U‘P‘PD 10. 11.‘ 12. Physics 227 — Hourly...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: .U‘P‘PD 10. 11.‘ 12. Physics 227 — Hourly Exam 1 ' Thursday, October 6, 2011, 9:40 PM'- 11:00 PM ARC—103 (A—I), SEC—111 (J—M), PLH (N—R), ELL-114 (S—Z) Your name sticker with exam code 7°91 Use a #2 pencil to make entries on the answer sheet. Enter the following ID information now, before the exam starts. - In the section labeled NAME (Last, First, Ml.) enter your last name, then fill in the empty circle for a blank, then enter your first name, another blank, and finally your middle initial. Under STUDENT # enter your 9-digit RUID Number. Under CODE enter the exam code given above.- Enter 227 under COURSE. You do not need to write anything else on the . answer sheet for now, but you may continue to read the instructions. During the exam, you may use a calculator and are allowed one 8.5 x 11 inch sheet of paper with whatever you want written on it. The exam consists of 16 multiple-choice questions. For each multiple~choice question mark only one no deduction of points for an incorrect answer, so even if you cannot work out the answer to a question, you should make an educated guess. ‘ If you have questions or problems during the exam, you may raise your hand and a proctor will assist you. If you need the value of a physical constant that is not given, we will provide it. It is your responsibility to know the ' relevant equations. A proctor will check your name sticker and your student ID sometime during the exam. Please have them ready. You are not allowed to share your calculator or help any other student, ask for help from anyone but a proctor, or change your seat without permission from a proctor. Doing so will result in a zero score for the exam. When you are done with the exam, hand in only this cover sheet and your answer sheet. Please sign above by the name sticker to indicate that you have read and understood these instructions. It might help to know 60 z 8.85 X10"12 CZ/N~m2, or k: : 1/47T60 = 8.99 X 109 N~m2/CZ. ' An insulating spherical shell of inner radius a and outer radius bis uniformly charged with a positive charge density. The radial component of the electric field, EAT) has a graph abr ‘ E take/«€82ch QCW ganja A. potential difference of 500 kV is established between parallel plates in air. The air becomes electrically conducting when the electric field exceeds 3.00 X 106 V/m. What is the separation of the plates when the air becomes a conductor? , a) 0.600mm - V9E& b) 0.167mm - - *0 DEV ' a» . M ‘C 1.67 mm ‘ 6LT» V“: v~ ‘5 .j/gsx goéV/Vh Aw talcum. lé’lffii‘crrf/ e) 0.600 cm A dielectric—filled parallel—plate capacitor has a plate area of A=0.300 m2, plate separation of d=9.00 mm, and dielectric constant'K=2.50. The capac— itor is connected to a battery that creates a constant voltage of V=15.0 V. How much energy U is stored in this dielectric—filled capacitor? a) 3.32x10‘“8J \ “a. - 2 C :2 L ‘ b) 4.15x10—3'J u 2 V C” \ Edam c) 0.55x10-8J ' d) 6.47x10-8 J r ,3, 250 «F. 0 wme f .— 3 e 8T3‘0x10:® H ‘ 7:) < j “’3 . OK M0 _ J 4. Three point charges are located on the roads: q1 = —e at a: = 0, qz = +6 ' at a: = a, and Q3 2 +6 at a: = 2a. Calculate the potential energy of the system of three charges. “EL 4&5, a) —82 /47reoa §>~——~~~t~w-w-w*tw~ b) +ez/87reoa \ Ce 7?“ & W787reoa 2; 1.. ye} Q}, “a; M. d +e 60a ' ‘ M3530 ‘5” Jr W.» —» m 3 :2“. “r? em a e) —e2/47reoa.2 ‘ a 2A“ M?“ W rl \ E W A 0d?“ a (f 5. A very long glass rod of radius 0.005 m carries a uni— 2%? form charge distribution with an unknown charge per unit length. At a distance of 0.30 m away from the axis of the E )5 a are; E rod, the electric field is measured to be 200 V/m, pointing <—-—-—-o - N towards the rod. The charge per unit length is izfi7ig8§wnglzjl a) —1.77 nC/m yioquww b) —7.43 nC/m fl 5 "pf c) _—2.00 nC/m ’ 33>“:‘éL-W f: ) ~373‘4ufingLnf) L i e I ~0l5690fiffi1‘C/m H 0.3 m—el 6. Consider a conductor in electrostatic equilibrium. Then, any net charge on the conductor must reside on the surface. b) the electric field cannot have a component perpendicular to the sur— "Q L 5:, (3“! {i9 face. I c) the electric potential must be zero inside the conductor. e“ 13- C’) V: C‘M’ém MA“ d) the electric field must be zero at the conductor’s surface. —- é“ a O I Q L :2 @739 e) work is done by the electric field to move a charge on the surface. ' a, g r‘ I a.” 7. In a certain region of space, the electric potential is V(x,y,z) 2 A562 + 'Bzy + C'y + D where A, B, C and D are positive constants. At which of ‘these points is the electric field equal to zero? \ I I 4 I p 9* :1 , 3;)? {V girthx w Elk—.9: ‘3 a“: a) z=0,y=0,z=0 g},- b) $=C,y=—2AC‘,Z=O , v (91"? x Q r1 c) 95:0/3, yz—ZAO/B, 2:0 leg; wt :3; W = I; “33% 4 “w *3; d) 2220 =~B =0 W5 , _ . v A~~ 7-7.Z.r,.i..m...-__mmy“ “Lu-MW,”wa b c) \ fie) $=—C’/B,y=+2AC‘/Bz,z=D:¥ 9;, =- «9 1? {,vi 2 C3 Kmfiw l w.”.WW'WWM“wwwmw'm‘"WW“ fl T’ ‘ {3M5 .QIQ'QA: LAC Uzi/i 5 0 (guy? (:3 *5} @X‘Hr“: L \5 z. «w Cr 5’53») 3' fivmgé‘} “LAWN? “43’ S w ;A “(a \‘ 9,50 “9, x , 9H.‘*~ a. n’ «J‘Rfi‘w :91 {M } L M‘ 8. Two point ‘charges lie along the x—axis: a +4MC charge at a: = +2crn and a +9/LC charge at a: = —-3 cm. The electric field at the origin is: . I .. n w a) (5 x 10-4 N/Cfi - 5 b 1 x 108 N/Cfi " V was“ “(A 4:) d) (1.8 x 10811702 J ,3 e) (—1x10“4N/C)i $591311, " " . an??? : ,mi'mv 4» 0171-10“? :1. (:3 g! 9. What is the force between a charged plastic insulator and a neutral metal conductor? a) F=0 b) F is repulsive c) F is attractive for positive—charged plastic, repulsive for negative charged. . d) F is attractive for negative—charged plastic, repulsive for positive char ed. F 5 fl e F is attractive 9"" E {aflgfi‘gefimfiv a; 10. Three capacitors are connected by conducting wires as shown. 01:10 uF, 02:40 p.F, 03:2 MF. What is the equivalent capacitance Ceq? C\ (3/02 \V‘ _ €39 a 'r 1" 61$ \ ‘1. ml: mm?) a C‘wrzé “3’ a a Cl 1" j} I 1:3 g. ‘ '5 m» r «0 C3 1 Ceq alt-(£16, m (:5 1 33 1—1 C t? WW C2 c) 1.6 pF (:1‘ 1656a,. «4272 m d) 1.92111? ,gmallal ', e) 2.13111? 0 Ce?) £17,033 ‘ , ; 1:. WE? 11. A point charge Q1 2 +4.00 n0 is located on the z-axis at a: = 10 cm, and a second point charge Q2 = ——2.00 710 is located on the y-axis at y = —-10 cm. A spherical Gaussian surface with radius 7" =2 15 cm is centered at the origin. The flux through this Gaussian surface w... .9“:er “5‘ a) +452 N/C ‘ b) +452 Nrnz/C c) +226 N/C d , .,.6.7.5...1\11r113.[Q~ e) +226 NmZ/Q} \3 v1 “W3 «mm X 1:547 His- ef..l(g.c;\v°l n {$14) £32! Pain; '5 W 1221 W *3 12. 13. 14. 15. This figure shows electric field lines in the plane through the centers of five spherical Gaussian surfaces, labeled A through E. Of these, the following have zero net flux through ) 0 and A only ) none of them ) all of them ) E only Two charges, one of +7 #0 and one of ~4 ,uC, are 0.3 m apart. How much work must be done to bring a charge of ~5 #0 to form the third vertex of an equilateral triangle, 0.3 m from each of the others? to the dipole moment of the dipole. What is the magnitude of the torque A, “a 01-1“ all/wages.) a f" . .\ . ., .. “Ms was an” be». mg ff 0 snag. W 3‘.» R . a, £5}, 5;.) :2; a) ~0.84 J m a l; Cgb‘ b) ~1.29 J w” U‘ 3? "“ .35.. i C) i 0 ‘ \ ‘5? 2. . d —1.5 J , m (:7 wove qwfi— x, ‘me LN mflggfhmj ‘ 1.7 - Q \ 1% ‘ Two point charges of magnitude q and of opposite signs are separated by a :7 ? distance d, forming an electric dipole. The charges are in a uniform electric M; 449 I) ' field of magnitude E whose direction makes an angle 6 = 30° with respect on the electric dipole? N «K g: u . h ., .3 Chg“, —- &ESH\5 a) qE/2 L W V ’4 E . 96 C6 1 b) qu 3%“be if?» c) zero (f I qéE 2 v“ g. e) $877532? 6 The energy density on a parallel—plate capacitor stays the same when its dimensions (length x width x plate separation) are all doubled. By what factor does the stored energy change? a) 1 ; V'Dluvtxer; ions/2 Ul “* y ~ '~ (<23, a)» ‘1; e) 2 16. A total electric Charge of 5.00 n0 is distributed uniformly over the surface ' of a metal sphere with a radius of 20.0 cm. The potential is zero at infinity. What is the potential at 10.0-cm from the center of the sphere? a) infinity b) zero 0) 112 V d 50 V e) 225 V ...
View Full Document

Page1 / 6

ES1F11 - .U‘P‘PD 10. 11.‘ 12. Physics 227 — Hourly...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online