Electricity Test Review

Transcription

1 Please aswer the questos o a separate sheet of paper. ocepts: Electrcty Test evew 1. What s your rule for determg how addg bulbs to a crcut affects resstace? Look at secto 3 of the lab.. What s your role for determg how addg bulbs to a crcut affects flow? Look at secto 3 of the lab. 3. What s the dfferece seres ad parallel? Look at secto of the lab. 4. How do you fd the uvalet resstace of resstors parallel? Look at your Ohm s Laws otes. 5. How do you fd the uvalet resstace of resstors seres? Look at your Ohm s Laws otes. 6. What s Ohm s law ad why does t t always apply? Look at your Ohm s Laws otes. 7. What s a short ad how do you create t? Look at ay secto of the lab. 8. Draw the symbols for a battery, bulb, swtch, ad resstor. Look at secto 1 of the lab. 9. Why does the symbol for a bulb have two detcal termals? Look at secto 1 homework. 10. What s oulomb s law? Look at oulomb s law otes. 11. What s superposto? Look at oulomb s law otes. 1. How are Amperes related to oulomb s? Look at Ohm s law otes. 13. What s the dfferece a sulator ad a coductor? Look at oulomb s law otes. 14. Is charge coserved? Look at oulomb s law otes. 15. What s the dfferece parallel braches that are depedet ad depedet across the battery? Look at secto 3 of the lab. 16. What does the pref mcro, µ, mea? Serously, you have a phoe, a computer, ad you re askg me. ;P 17. The potetal dfferece across the eds of a wre s doubled magtude. If Ohm s law s obeyed, whch oe of the followg statemets cocerg the resstace of the wre s true? (a) The resstace s oe half of ts orgal value. (b) The resstace s twce ts orgal value. (c) The resstace s ot chaged. (d) The resstace creases by a factor of four. (e) The resstace decreases by a factor of four. Problems: 1. Two solated charges +q ad -q, are cetmeters apart. If F s the magtude of the force actg o the charge -q, what are the magtude ad drecto of the force actg o charge +q? F the opposte drecto.. Fd the uvalet resstace betwee X ad Y the two crcuts show below. Left (4 )( ) 4 (4 ) 3 rght ( )( ) 3 ( ) 3. I the crcut o the above left, 1 A eter the brach at X ad et at Y. What s the curret through each resstor? Assume s the curret the 1 Ω ad 3 Ω resstor ad 6 s the curret the Ω resstor. + y = 1 A. ad = y so + = 1 A thus, = 4 A ad y = 8 A

2 4. A pot charge q1 = 4.0 µ s at the org ad a pot charge q = 6.0 µ s o the as at = 3.0 m. Fd the electrc force o charge q? 4.0 µ = µ = 3 m 6 6 k(410 )(610 ) F 0.04 N,180 (3 m) 5. For problem 4 above, what s the electrc force o q1? N, 0º 6. How would your aswers to 4 ad 5 chage f q = -6.0 µ? Both forces would be the opposte drecto. 7. A -.0 µ pot charge ad a 4.0 µ pot charge are a dstace L apart. Where should a thrd pot charge be placed so that the electrc force o the thrd charge s zero? -.0µ L +4.0µ The pot where there s zero et force has to be closer to the smaller charge. It ca t be betwee the two forces because the et force would be to the left. Thus, the pot where the force s zero s o the left sde of the charges. k( ) q k(4 ) q L 1 L L L L L L 0 L 4L 4L L L L L(1 ) 8. Three pot charges, each of magtude 3.00 µ, are at separate corers of a square of edge legth 5.00 cm. The two pot charges at opposte corers are postve, ad the thrd pot charge s egatve. Fd the force eerted by these pot charges o a fourth pot charge q4 = 3.00 µ. 3µ 3µ F 1 F 3 3µ 3µ F

3 k(310 ) F1 (.05 m) 6 F 3.4, 70 6 k(310 ) F3 ( (.05 m)) 3.4 N, N,45 F Theta y F = -( j) N = 9.6 N, 5º 9. A wre carres.00 A of curret for 3.00 secods. What s the charge that passes through that wre durg that tme? q=t = (/s)(3s) = What s the umber of electros that move through the wre #9 durg that tme perod? electro electros How may electros flow through a battery that delvers a curret of.0 A for 15 s? q=t = (/s)(15s) = 30 electro electros A 10-A curret s mataed a smple crcut wth a total resstace of 00 Ω. What et charge passes through ay pot the crcut durg a 1-mute terval? q=t = (10/s)(60s) = 600 electro electros Whe a lght bulb s coected to a 4.5 V battery, a curret of 0.16 A passes through the bulb flamet. What s the resstace of the flamet? V 4.5V A 14. Three resstors, 50- Ω, 100- Ω, 00- Ω, are coected seres a crcut. What s the uvalet resstace of ths combato of resstors? 350 1

4 15. A 4.5-V battery s coected to two resstors coected seres as show the drawg. What s the curret the crcut? 4.5 V V 4.5V 0.033A Two 0- Ω ad three 30- Ω lght bulbs ad a 15 V battery are coected a seres crcut. What s the curret that passes through each bulb? (0) 3(30) 13 1 V 15V A Fve resstors are coected as show. What s the uvalet resstace betwee pots A ad B? I A 4.0 (4 )( ) (3 )(3 ) (4 ) (3 3 ) B 18. Jaso s crcut has a 4- Ω resstor that s coected seres to two 1- Ω resstors that are coected parallel. JoAa s crcut has three detcal resstors wred parallel. If the uvalet resstace of Jaso s crcut s the same as that of JoAa s crcut, determe the value of JoAa s resstors. for Jaso: (1 )(1 ) 4 30 (1 1 ) for Joaa: 1 1 r r r r r r 90 Questos 19 through 0 perta to the statemet ad dagram below: Four resstors ad a 6-V battery are arraged as show the crcut dagram. 6 V

5 19. Determe the uvalet resstace for ths crcut. for the brach o the rght: (30 )(60 ) (30 60 ) combg the left ad rght brach: (0 )(30 ) 1 (0 30 ) 0. Whch resstor has the smallest curret passg through t? 60Ω