PHY3054 - Exam 2 - Fall 1996 - Selman Hershfield
1. In Fig. 1 each of the resistors are light bulbs with identical resistance. List the light bulbs from the dimmest to the brightest. Group light bulbs with the same brightness in parentheses.

1. dimmest (BDEF), (AC) brightest
2. dimmest (BF), (AC), D, E brightest
3. dimmest (BF), (AD), (CE) brightest
4. dimmest (BF), (CE), D, A brightest
5. dimmest (BDF), E, (AC) brightest

2. In Fig. 1 what is the voltage difference between points P1 and P2, VP1 - VP2 ?

1. 0 V
2. 2 V
3. 3 V
4. 4 V
5. 6 V

3. What is the effective resistance of the circuit shown in Fig. 2? (Choose the closest answer.)

1. 1 Ohm
2. 2 Ohms
3. 4 Ohms
4. 6 Ohms
5. 10 Ohms

4. In Fig. 3 if the voltage across R1 is 2 V, what is the current through R5 ? (Choose the closest answer.)

1. 0.2 A
2. 0.7 A
3. 1.0 A
4. 1.4 A
5. 2.4 A

5. In Fig. 4 what is the current in the circuit? Give both the magnitude and direction. (Choose the closest answer.)

1. 0 A
2. 0.5 A clockwise
3. 0.5 A counterclockwise
4. 0.75 A clockwise
5. 0.75 A counterclockwise

6. In Fig. 5 what is the current from E to B? (Choose the closest answer.)

1. -1.3 A
2. -0.75 A
3. -0.6 A
4. 0.6 A
5. 1.3 A

7. In Fig. 5 what is the voltage difference, VD - VF ?

1. -6.25 V
2. -4.9 V
3. 4.9 V
4. 5.5 V
5. 6.25 V

8. In Fig. 6 what is the effective capacitance of the circuit? (Choose the closest answer.)

1. 0.4 micro-F
2. 0.625 micro-F
3. 1.6 micro-F
4. 3.5 micro-F
5. 5.1 micro-F

9. In Fig. 7 if the voltage across C4 is 2 V, what is the charge on C2 ? (Choose the closest answer.)

1. 2 micro-C
2. 4 micro-C
3. 6 micro-C
4. 8 micro-C
5. 10 micro-C

10. Place your name, social security number, and exam number on your bubble sheet -- NOW. Also, print and sign your name on the exam printout.

1. Done correctly
2. Done incorrectly
3. Done incorrectly
4. Done incorrectly
5. Done incorrectly

11. Determine the magnitude of the magnetic field at point P in Fig. 8.

1. 0 Tesla
2. 4x10-5 Tesla
3. 8x10-5 Tesla
4. 12x10-5 Tesla
5. 16x10-5 Tesla

12. In Fig. 9 three wires carry current perpendicular to the plane of the page. Each wire carries the same magnitude current, but wires A and B have current flowing out of the page, while wire C has current flowing into the page. What is the direction of the force, F, on each of the wires?

1. F on A to the left, F on B to the left, F on C to the right
2. F on A to the left, F on B to the right, F on C to the right
3. F on A to the left, F on B to the right, F on C to the left
4. F on A to the right, F on B to the left, F on C to the left
5. F on A to the right, F on B to the left, F on C to the right

13. What is the direction of the force on the wire in Fig. 10.1, and what is the direction of the force on the rectangular loop in Fig. 10.2?

1. F on wire is in and F on loop in Fig. 10.2 is up
2. F on wire is out and F on loop in Fig. 10.2 is up
3. F on wire is in and F on loop in Fig. 10.2 is down
4. F on wire is out and F on loop in Fig. 10.2 is down
5. none of the above

14. Which direction is the loop in Fig. 11 turning and what direction is the magnetic moment pointing?

1. clockwise and M is up
2. clockwise and M is down
3. counterclockwise and M is up
4. counterclockwise and M is down
5. none of the above

15. In Fig. 12 there are different magnetic fields in Region I and Region II. A positively charged particle follows the path indicated in the figure. Which of the following is true of the magnetic field in Region II?

1. B in II is into the page and larger in magnitude than B in I.
2. B in II is out of the page and larger in magnitude than B in I.
3. B in II is into the page and smaller in magnitude than B in I.
4. B in II is out of the page and smaller in magnitude than B in I.
5. none of the above

16. Three wires carry current perpendicular to the plane of the page as shown in Fig. 13. If the magnitude of the current is the same in each wire, what is the direction of the magnetic field at point P?

1. 70 degrees
2. 160 degrees
3. 200 degrees
4. 250 degrees
5. 290 degrees

17. You are given two 1 kilo-Ohm resistors, which may be combined in either series or parallel, and you are given two 1 micro-Farad capacitors, which may be combined in either series or parallel. What is the largest time constant you can make in an RC circuit from these resistors and capacitors?

1. 1 milli-second
2. 2 milli-seconds
3. 4 milli-seconds
4. 8 milli-seconds
5. 16 milli-seconds

18. In Fig. 14.1 the current in the left loop is decreasing. In Fig. 14.2 the loop is moving away from the wire. What is the direction of the induced current in the right loop of Fig. 14.1 and the loop in Fig. 14.2?

1. clockwise in 14.1 and clockwise in 14.2
2. counterclockwise in 14.1 and clockwise in 14.2
3. clockwise in 14.1 and counterclockwise in 14.2
4. counterclockwise in 14.1 and counterclockwise in 14.2
5. none of the above

19. The space shuttle is traveling around the earth with a velocity of 8000 m/s. A satellite is connected to the shuttle via a conducting tether 20 km long. The satellite is positioned radially outward from the shuttle because of the shuttle's centripetal acceleration. If the magnetic field is pointing due north with magnitude 0.5x10-4 Tesla, what is the magnitude of the motional emf in the tether (a) when the shuttle is traveling east and (b) when the shuttle is traveling north?

1. (a) 0 V (b) 0 V
2. (a) 0 V (b) 8000 V
3. (a) 8000 V (b) 0 V
4. (a) 8000 V (b) 8000 V
5. none of the above

20. Fig. 15 shows a snapshot of an AC generator. Given the indicated direction of the induced current, which of the following is true?

1. The loop is rotating clockwise, and the flux is a maximum.
2. The loop is rotating counterclockwise, and the flux is a maximum.
3. The loop is rotating clockwise, and the flux is zero.
4. The loop is rotating counterclockwise, and the flux is zero.
5. None of the above.

1. Answer = (1) dimmest (BDEF), (AC) brightest
2. Answer = (5) 6 V
3. Answer = (2) 2 Ohms
4. Answer = (2) 0.7 A
5. Answer = (2) 0.5 A clockwise
6. Answer = (5) 1.3 A
7. Answer = (2) -4.9 V
8. Answer = (3) 1.6 micro-F
9. Answer = (5) 10 micro-C
10. Answer = (1) Done correctly
11. Answer = (1) 0 Tesla
12. Answer = (5) F on A to the right, F on B to the left, F on C to the right
13. Answer = (2) F on wire is out and F on loop in Fig. 10.2 is up
14. Answer = (4) counterclockwise and M is down
15. Answer = (1) B in II is into the page and larger in magnitude than B in I.
16. Answer = (4) 250 degrees
17. Answer = (3) 4 milli-seconds
18. Answer = (2) counterclockwise in 14.1 and clockwise in 14.2
19. Answer = (3) (a) 8000 V (b) 0 V
20. Answer = (4) The loop is rotating counterclockwise, and the flux is zero.