(Sample 3) Exam 1 - Physics Patel SPRING 1998 FORM CODE - A (solution key at end of exam)

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1 (Sample 3) Exam 1 - Physics Patel SPRING 1998 FORM CODE - A (solution key at end of exam) Be sue to fill in you student numbe and FORM lette (A, B, C) on you answe sheet. If you foget to include this infomation, you Exam will not be counted towads you gade. Each question may have one answe which is moe coect than the othes. Be sue to ead all five answes so than you will not miss the best one. The last page has a list of equations you may find useful and may be detached fo use duing the exam. 1. Exta Cedit: What is you fom code? (a) A (b) B (c) C (d) I don't want any exta cedit. (e) 2

2 2. The diagam shows two pais of heavily chaged plastic cubes. Cubes 1 and 2 attact each othe and so do cubes 1 and Which of the following illustates the foces of 2 on 3 and 3 on 2? (A) (B) (C) (D) (E) 3. A positively chaged metal sphee A is bought into contact with an unchaged metal sphee B. As a esult: A. both sphees ae positively chaged B. A is positively chaged and B is neutal C. A is positively chaged and B is negatively chaged D. A is neutal and B is positively chaged E. A is neutal and B is negatively chaged

3 4. Two small chaged objects epel each othe with a foce F when sepaated by a distance d. If the chage on each object is educed to one-fouth of its oiginal value and the distance between them is educed to d/2 the foce becomes: A. F/16 B. F/8 C. F/4 D. F/2 E. F 5. Chage Q is on the y axis a distance 'a' fom the oigin and chage q is on the x axis a distance 'd' fom the oigin. The value of d fo which the x component of the foce on q is the geatest is: A. 0 B. a C. 2a D. a/2 E. a 2

4 6. Point chages ae located at two vetices of an equilateal tiangle and the electic field is zeo at the thid vetex. We conclude: A. the two chages have opposite signs and the same magnitude B. the two chages have opposite signs and the diffeent magnitudes C. the two chages ae identical D. the two chages have the same sign but diffeent magnitude E. at least one othe chage is pesent 7. The diagam shows the electic field lines due to two chaged paallel metal plates. We conclude that: Y Z metal plates X A. the uppe plate is positive and the lowe plate is negative B. a positive chage at X would expeience the same foce if it wee placed at Y C. a positive chage at X expeiences a geate foce than if it wee placed at Z D. a positive chage at X expeiences less foce than if it wee placed at Z E. a negative chage at X could have its weight balanced by the electical foce

5 8. Positive chage Q is unifomly distibuted on a semicicula od. What is the diection of the electic field at point P, the cente of the semicicle? Q P A. B. C. D. E. 9. When the dipole moment of a dipole in a unifom electic field otates to become moe nealy aligned with the field: A. the field does positive wok and the potential enegy inceases B. the field does positive wok and the potential enegy deceases C. the field does negative wok and the potential enegy inceases D. the field does negative wok and the potential enegy deceases E. the field does no wok

6 10. A unifom electic field of 300 N/C makes an angle of 25 with the dipole moment of an electic dipole. If the moment has a magnitude of 2 x 10-9 C m, the toque exeted by the field has a magnitude of: A. 6.7 x N m B. 2.5 x 10-7 N m C. 5.4 x 10-7 N m D. 6.0 x 10-7 N m E. 2.8 x 10-7 N m 11. The flux of the electic field (24 i 30j 16 k) N/C though a 2.0 m 2 potion of the yz plane is: A. 32 N m 2 /C B. 34 N m 2 /C C. 42 N m 2 /C D. 48 N m 2 /C E. 60 N m 2 /C

7 12. A point chage is placed at the cente of a spheical Gaussian suface. The electic flux φ E is changed: A. if the sphee is eplaced by a cube of the same volume B. if the sphee is eplaced by a cube of one-tenth the volume C. if the point chage is moved off cente (but still inside the oiginal sphee) D. if the point chage is moved to just outside the sphee E. if a second point chage is placed just outside the sphee 13. Which of the following gaphs epesents the magnitude of the electic field as a function of the distance fom the cente of a solid chaged conducting sphee of adius R? E E E R R R A B C E E D R E R

8 14. A chage Q is placed on a conducting spheical shell with inne adius R 1 and oute adius R 2. A point chage q in placed at the cente of the cavity. The magnitude of the electic field at a point outside the shell, a distance fom the cente, is: A. Q/4πε o R 1 2 B. Q/4πε o (R ) C. q/4πε o 2 D. (q Q)/4πε o 2 E. (q Q)/4πε o (R ) 15. Two lage INSULATING paallel plates cay positive chage of equal magnitude that is distibuted unifomly ove thei sufaces. Rank the points 1 though 5 accoding to the magnitude of the electic field at the points, least to geatest A. 1,2,3,4,5 B. 5,4,3,2,1 C. 1, 4, and 5 tie, then 2 and 3 tie D. 2 and 3 tie, then 1 and 4 tie, then 5 E. 2 and 3 tie, then 1, 4, 5 tie

9 16. A 5.5 x 10-8 C chage is fixed at the oigin. A -2.3 x 10-8 C chage is moved fom x = 3.5 cm on the x axis to y = 3.5 cm on the y axis. The change in the potential enegy of the two-chage system is: A. 3.2 x 10-4 J B x 10-4 J C. 9.3 x 10-3 J D x 10-3 J E Duing a lightning dischage, 30 C of chage moves though a potential diffeence of 1.0 x 10 8 V in 2.0 x 10-2 s. The enegy eleased by this lightning bolt is: A. 1.5 x J B. 3.0 x 10 9 J C. 6.0 x 10 7 J D. 3.3 x 10 6 J E J

10 18. Thee possible configuations fo an electon e and a poton p ae shown below. Take the zeo of potential to be at infinity and ank the thee configuations accoding to the potential at S, fom most negative to most positive. D d D d d e S p S e p S p 1 2 D A. 1, 2, 3 e 3 B. 3, 2, 1 C. 2, 3, 1 D. 1 and 2 tie, then 3 E. 1 and 3 tie, then The equipotential sufaces associated with an isolated point chage ae: A. adially outwad fom the chage B. vetical planes C. hoizontal planes D. concentic sphees centeed at the chage E. concentic cylindes with the chage on the axis.

11 20. Each plate of a capacito stoes a chage of magnitude 1 mc when a 100 V potential diffeence is applied. The capacitance is: A. 5 µf B. l0 µf C. 50 µf D. 100 µf E. none of these 21. The plate aeas and plate sepaations of five paallel plate capacitos ae capacito 1: aea A o, sepaation d o capacito 2: aea 2A o, sepaation 2d o capacito 3: aea 2A o, sepaation d o /2 capacito 4: aea A o /2, sepaation 2d o capacito 5: aea A o, sepaation d o /2 Rank these accoding to thei capacitances, least to geatest. A. 1, 2, 3, 4, 5 B. 5, 4, 3, 2, 1 C. 5, 3 and 4 tie, then l, 2 D. 4, 1 and 2 tie, then 5, 3 E. 3, 5, 1and 2 tie, 1, 4

12 Some Useful Fomulae Electon chage -1.6 x C Electon mass 9.11 x 10-3l kg Poton mass 1.67 x kg 1 k E = 4πε = 9 x 109 kg m 3 s -2 C -2 0 ε 0 = 8.85 x F m µ 0 = 4π x 10-7 N 2 A Coulomb's Law kq1q2 F = 2 Field aound Pt chage E = Potential aound Pt chage ( ) kq V = 2 kq kq Q 1 2 Potential E. due to a pai of Pt chages U ( ) = 12 Electic Potential V = E dl line Capacitos in Seies =... C eq C1 C1 Capacitos in Paallel C eq = C 1 C 2 Q Capacitance C = V 1 2 Enegy of a Chaged Capacito U = CV 2 Electical Flux Though a Suface Φe = E da suface Q Gauss' Law E da = enc ε 0

13 Answes 2 (B) 3 (A) 4 (C) 5 (E) 6 (E) 7 (B) 8 (D) 9 (B) 10 (B) 11 (D) 12 (D) 13 (C) 14 (D) 15 (E) (REMAINING QUESTIONS DO NOT APPLY TO SPRING 99 MID TERM1 )

Physics 2212 GH Quiz #2 Solutions Spring 2016

Physics 2212 GH Quiz #2 Solutions Sping 216 I. 17 points) Thee point chages, each caying a chage Q = +6. nc, ae placed on an equilateal tiangle of side length = 3. mm. An additional point chage, caying