                        EOC Goal 9
Accessed 10 June 2017 at http://www.NCpublicschools.org
released October 2004

 A B C D
1. In which of the following cases is the force between the charges the greatest?
1. 2. 3. 4. A B C D
2. Two positive charges of 6.0 × 10−6 C are separated by 0.50 m. What force exists between the charges?
1. 6.5 N
2. 1.3 N
3. 2.3 × 10−9 N
4. 3.6 × 10−11 N
 A B C D
3. If charges of +10.0µC and −50.0 µC are separated by 0.200 m of air, what electrostatic force will the charges experience?
1. +224 N
2. +112 N
3. −112 N
4. −224 N
 A B C D
4. Two charges, +3 × 10−6C and +2 × 10−6C, are separated by a distance, d, and experience a repulsive force of 1.35 × 10−2 N. What is the value of d?
1. 1 m
2. 2 m
3. 4 m
4. 16 m
 A B C D
5. Two charges separated by a distance d exert a force F on each other. What is the force between the same charges if the distance is increased to 2d?
1. ¼F
2. ½F
3. 2F
4. 4F
 A B C D
6. How far apart are two electrons if they exert a force of 3.0 N on one another?
1. 2.3 × 10−10 m
2. 2.6 × 10−14 m
3. 8.8 × 10−15 m
4. 7.8 × 10−29 m
 A B C D
7. Two equal charges, separated by a distance of 2 m, experience a force of 0.02 N. What are the magnitudes of the two charges?
1. 3 µC
2. 4 µC
3. 7 µC
4. 9 µC
 A B C D
8. A charged particle enters a region of magnetic field of 4.0 × 10−4 T with a speed of 3.0 × 106 m/s and experiences a force of 2.4 × 10−3 N. What is the magnitude of charge on the particle?
1. 5.6 × 10−8 C
2. 2.0 × 10−6 C
3. 2.9 C
4. 3.1 × 1012 C
 A B C D
9. Three particles enter a region of uniform magnetic field (pointing out of page) and deflect as shown below. Which of the following statements is correct about the charge on the particles?
1. 1 is positive, 2 is neutral, 3 is negative.
2. 1 is negative, 2 is negative, 3 is positive.
3. 1 is positive, 2 is positive, 3 is negative.
4. 1 is negative, 2 is neutral, 3 is positive.
 A B C D
10. Two parallel wires are carrying current and an attractive force exists between them. Which description applies to the wires?
1. Current flows in opposite directions in the wires.
2. Current flows in the same direction in both wires.
3. The wires attract regardless of the direction of the current.
4. This does not happen because the force is always one of repulsion between the wires regardless of the direction of current.
 A B C D
11. Note: The Xs represent a magnetic field directed into the paper. What is the direction in which a positive charge is deflected when it enters the magnetic field as shown above?
1. 2. 3. 4.  Additional North Carolina Exam Questions