PHYS 211 Final, Spring 2008

PHYSICS 211 NEWEST QUIZZI & FINALS 1997 QUIZZES ARE INCLUDED 1998 — 1999 EDITION ~s 1, S AMERICAN UNIVERSITY OF BEIRUT Physics 211 Quiz I Time: T hour April 8, 1998 Question 15% Four identical point charges of Q coulomb are located at the corners of a square, = 90x 10?Nm? /C? 4ime 0 Q=5x1oee d 0 LAYd &{ How much work must be done to completely separate the four charges from one another ? bf Find the force ( magnitude and direction) ? one point charge of 2Q coulomb located at the center of the square . C\ Find the force (magnitude and direction) on the charge at the center of the square when one of the corner charges ts removed. Question TL 15 % The electric potential at the A.B & C, the corners ofan equilateral triangle with a side of 0.5 m, are respectively : 7 LOY, +15V, & -12V. How much work (siga & magnitude in units of eV, the charge of the proton is te) must be done to move 2 proton at constant speed. a) From A via BtoC b) From A via C to B c) From A viaC and Bto A d)- From CtoA Solation: 1 2 ALE g x( av2)~ direction to the empty corner Question LU Ver Vae AV=-12-10=-22V W = qAV=-22 eV nen b) e A -» B Va- Vayu AVe= 15-1085 V We qAV=5eV c) e A - A AV=OV W=0V dl) es -(A -» C) Woe 22 eV a a Question UE a) QE=-Q f XL b) cab rab Pa - Gnet dine Ve~ fEds=— f - Sock dr= Aner 4negr* ane gb Gret ~ Q * Ol + Q2 faesenne n> Q2 = Cnet = 4negb Vv r>b: pe inet See0bV _ bY 5 5 ARE gt” 4negr~ cm ¢ Nae! uestion LV 30% i a Two large, parallel, metal plates of area 4 mv" * face each other & cx equal and € opposite charges on their inner surfaces. The notential difference between tne plates is 550 VY. A proton, placed at a distance of ed plate experiences a force of 8.8x10 ON 3 cm from the positively chat =90x 10° Nim” ic; Axe Q e=160x 107°C Lo7 x lO ~' Kg 2a 88x 1071? F/m a) Find the distance d between the plates ? b) What is the total charge on the plates ? c) Another proton, placed midway between the two plates, moves towards the negatively charged plate with a velocity Vy, what should the magnitude & direction of Vy be in order that the proton just comes at rest in front of the negatively charged plate ? nil 40% A spherical conductor of radius a has a charge Q placed on it. This spherical conductor is surrounded by a thin, conducting spherical shell (concentric) of radius b. The shell is kept at constant potential V. a) Find the charge QI on the inner surface of the shell ? b) Find the charge Q2 on the outer surface of the shell ? cl Find the electric field at a distance r from the center of the spherical conductor where r > by a<r<b; & r<a.? d) Find the electric potential at a distance r> b; acr<b; & r<al? r>b ee dr - bv Va- fi.ds= [Eds= -JEdr=—bV{ “ =4bV[1/rjh V ~ os on ae r asr<tb reb ; : 2 O Vu fi.ds - | QR sdr= V+ Qo ; pb ARE yr” dxegr 4iegb r<a Question TY F=eE = 8.8 x 10'°N E=(8.8 x 10° NV(.60 x 10°C) = $500 N/C V=Ed=550 V---> d= S50/E=O0.1m Bao - o =885xlol’xss00=49x108C/m Q= Area xo = 4x 4.9x 1078 = 19.6 x LO%C AV = 275V AU = cAV im Vp = 23x 10°m/s towards the +vely charged plate. MERIC: Time: ( hour Same = LD. vo, ----- Question f. (20%) Two long parallel wires run perpendic: al the \-aXxis at AXIS alihe pone ( ( | m, intersects the xy plane the xy plane on the x SN UNIVERSTI Physics 211 Quiz {ul 100 A out of the xy plane. and wire 2 ca xy plane. (Ug = 4 x 107 Ti mn) 4 Oak? 7 c an .\ ( e » ae the xy plane, find the ma Pind the magnetic induction field B point p in the xy plane, located at (]in, [tm). the point p. If the current in this third wire ts 1A, ¢ gnitude length exerted on the wir SOF BEI RUT June 10, arto the xy plane. Wire | a (0, fim rries ¢ A 1? ~ \ .* ! ay Vo gg { . ( Ne 1996 1). Wire 2 intersects 0 . Wire | carries a current of 2current of LOO A into the OY Gow ty (direction and magnitude} ata A third long wire ts parallel to the 2 other wires & passes through tirected out of and direction of the force per unit