13 Electric Field Tutorial

P a g e 1 1 of 1 1 show n below . p©¥aced at three corners of a square as P 2 P oint charges, e a c h of m agnitude Q , a re N 8 9/©¥/1 6 vertical. to m ake sm all angles Q A a nd w ith the repu©¥sion betw een them causes the threads has m ass 2 M and carries charge 2 Q . T he ©¥evel. A has m ass M and carries charge Q B fixed points P A and P B , a n d are at the sam e hung by light, n o n - conducting threads from P 1 T w o sm all conducting spheres A and B are J 85/1/1 8 force? 5 5 . W nat are the sim ilarities and differences betw een e©¥ectric force and gravitational charged paralle©¥ plates? fie©¥d and the potentia©¥ V at that point? W hat is the electric field strength betw een w nat is the relationship between the electric field strength E at a point in an electric5 4 . field w ith a ve©¥ocity that is perpendicular to the direction of the e©¥ectric field 5 3 . D escribe the m otion of a positively charged particle that enters a uniform electric (b) tw o point charges of equal m agnitude and opposite polarity . (a) tw o point charges of equal m agnitude and sam e polarity . 5 2 . S ketch the electric field ©¥lnea for 5 1 . D ellne electric f©¥eld strength and e©¥ectric potentia©¥ at a point. S e©¥f - C heck Q uest©¥one R est m ass of electron m . - e . 11 ¡¿ 1 0 - 3 1 kg E ©¥em entary cha ¡ß e o = 1 . 60 ¡¿ 1 0 - ©¥ ©¥ c P em rilivlty of free space ￡b ¡Æ 8 . 8 5 ¡¿ 1 0 ¢®l F m - ! D ata 1 3 E L E cT R ©¥C F ©¥E L D T uto rial Ë£ m Ù³ÔÒÞÀÚ¤卢Уϡ" µðêÖУУ«Éªæl pH Y 8 ©¥C 8 D E P A R TM E N T R A F F L E S IN S T TT U T ¨©O N

e direction indicated by an electric field P a g e 1 2 of 1 1 D W 72 ¨¤2 C W 72 ¨¤4 B W 74 ¨¤2 A W 74 ¨¤4 wq!Ķ. 4ąnę force values of w ork done and force? from the centre of the sphere, w hat are the ©¥f the sm all charge is now p©¥aced at 1 . 0 m final position w as F . W and the force on the sm all charge in its T he w ork done against the e©¥ectnc field w as center. point to a point 0 . 5 m from the sphere ' s A sm all charge w as brought from a distant large positive charge. insulated from its surroundings and given a P 7 A m eta©¥ sphere of radius 0 . 1 m was J821©¥1©¥21 D 4 ¨¡óv 2 ¡¤ e Q ^ 4 ¨¡D' - 4 nel * ©¡ eQ a at the centre l©¥ rem oved to ©¥nfinlly? electroatatic repu©¥a©¥on when the po©¥nt charge H ow m uch work ©¥©¥ done by the force©¥ of L T ī ©­ ©¥hown In the diagram . by ©¥©¥¡¿ ©¥dentlcal charges at d©¥stance r as P e A point charge is surrounded sym m etrical©¥y J8elU 1 6 D it does not experience a resultant force. aw ay from X . u it experiences a resultant force pushing it back to X . B it experiences a resultant force pulling it A its electric potential energy falls. ©¥f an electron m oves from X to Y , P 5 T he equipotential ©¥ines of a pair of point D tow ards P positive C towards P zero B tow ards Q negative A towards Q zero ęlęctricfieid ¡×! ę ņ ! į a ! point x? the electric fie©¥d and the electric potential at W W C h of the follow ing correctly describes P X Q + 2 2 between P and Q . at points P and Q respectively , X ©¥a m idway P4 T w o charges of + 2 and - 2 are situated N 97N©¥1 6 E the electric potential m uet decreaae, D the electric potential m uet ©¥ncreaee. C the electric potentia©¥ m ust rem a©¥n constant. B the e©¥ectric field etrength m uet decrease, A the e©¥ectric fie©¥d strength m uat ©¥ncrea©¥e. ©¥ine, P 3 Inth N 87©¥©¥©¥19 P H Y S ©¥C S D E P A R T M E N T raffles ©¥nsw w won

P a g e 1 3 of 1 1 4 0 4 0 4 0 4 0 A E v B V C 25 V D V point X and point Y ? W hat is the potentia©¥ di¨¤erence betw een m ¡ß ï£ï£ m 国 15 20 5 ľ V potential di¨¤erence betw een the plates is V . are situated 4 0 m m apart as show n. T he P 12 T wo large plane parallel conducting plates J97©¥l/1 6 the plates. E D ecrease the potential di¨¤erence betw een upwards. D M ove both plates the sam e distance charge. C G ive the positive plate m ore positive B R everse the charges on the plates. A M ove the p©¥ates closer together. rem ain stationary? changes should be m ade for the droplet to negative charge, w hich of the follow ing 10 , if the oil droplet acquires additional W ith reference to the diagram in questionP 1 d d q q A 业 B õç c ºê D »Ú is equal in m agnitude to F or this to occur, the w eight of the droplet potential - V . plate is at potential + V and the low er observed to be stationary w hen the upper T he separation of plates is d, T he droplet is - V - q + v m etal plates as show n in the diagram . situated betw een tw o parallel horizontal P 10 A n oi©¥ droplet has a charge - g and is J94©¥l11 5 ' , :.l E T he straight line X Q D A straight ©¥ine from X to R C A curved line from X to R B A straight line from X to P A A curved line from X to P path for the beam ? W W C h one of the fo©¥ïow ing is a possible directed as show n in the diagram . tube in w hich there is a uniform electric field P 9 A n electron enters a region in an evacuated N 88©¥©¥127 7 . 5 ¡¿1 0 ' ' 7 N D 7 . 5 ¡¿1 0 " N C 3 . B ¡¿1 0 " N electron? W hat is the m agnitude of the force on the 0 . . 020 > ¡¿/m E pl 1 0 - \ 6 1 plates as show n. varies w ith displacem ent x from one of the potential energy of an electron in the field producing a uniform electric field. T he P 8 T wo charged plates are 0 . 020 m apart, J 0 0 6 pH Y S ©¥C S D E P A R T M E N T R A FFLE S IN S T IT U T IO N

P a g e 1 4 of 1 1 between the two. D eterm ine the initial velocity of the third electron. D 2 . T wo electrons are fixed 2 . 0 cm apart. A third electron is shot » om infinity and com es to rest m idw ay the expression F - Öõ ì£ ì£ Ø² ¡£ Q Z E xp©¥ain w hy the force F betw een them ©¥s not given by apart as show n. each other in a vacuum w ith their centres distance d carrying a positive charge Q and are placed close to (b) A and B are two identical conducting spheres, e a ch x ìé Ľû»gj ' £¬ separation x, b e tw e e n the balls is given by approxim ation tan ů - s in ů - Q s h o w th a t th e charges q as show n. U sing the sm a©¥l angle non - c o n ducting threads of length I and carry sim i©¥ar T w o sim i©¥ar conducting balls of m ass m are hung fromD 1 . (a) 1 ev reach the plate P Q if the electron m ass is m electrons just G iven that the electron cfiãŕĝi is e and that J , .. i e 7 C 6 A 13 B 5 B 12 BP Q plates as show n 4 A 1 1 E velocity v enter the space betw een the 3 E 1 o B relative to a second plate M N . E lectrons of 2 A 9 A P Q is m aintained at a negative potential V 1 B 8 D P 13 ©¥n an evacuated enclosure, a m e ta ©¥ plate A nsw ers N 81©¥©¥m pH Y S ©¥C S D E pA R T M E N T R A F F L E S ©¥N S T ©¥T U T ©¥O N

P a g e 1 5 0 1 1 1 (b) the electric field strength E . ©¥ 4 d ' (a» the electric potential V , U L variation from A to B of S ketch graphs, o n e in each case, to show the . I. I . I d is situated central©¥y between the plates. placed a distance D apart. A conductor of thickness ¨¤ T wo large m etal plates are opposlte©¥y charged and D 6 . J87/©¥1©¥/6 line through the centre of the plates perpendicular to their planes, S ketch labelled graphs to show how the electric potential and electric field strength varies along a plates A and D are earthed, B is m aintained at a potential of + 3 0 V , a n d C at - 50 . V . arranged as show n in the figure below . T he distance between adjacent plates is 1 5 m m . T he outer F our square conducting plates A , B , C and D , e a c h of side 0 . 70 m and negligible thickness, a reD 5 . 1 ' 国 国 团团ÙÍì³ê®ÏÐ ' £¬ªÕ intensity E with the distance x. 2 \ S ketch a graph to show the variation of the electric along the x - a x is. potential V with the distance x * om a fixed point T he figure show s the variation of electrical v/vD 4 . the 3 . 00 ¡¿ 1 0 3 kg particle is 1 2 5 m s - 1 . D eterm ine the initial separation between the particles. released. T he partic