Please answer all questions.
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| 1 | |
How many electrons are contained in 1.0 C of charge? What is the mass of the electrons in 1.0 C of charge? |
| | A) | (a) 6.2 electrons, (b) 5.7 x 10-30 kg |
| | B) | (a) 6.2 x 1018 electrons, (b) 5.7 x 10-12 kg |
| | C) | (a) 6.2 x 108 electrons, (b) 5.7 x 1019 kg |
| | D) | (a) 1.6 x 1019 electrons, (b) 1.0 x 10-8 kg |
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| 2 | |
If two equal charges, each of 1 C, were separated in air by a distance of 1 km, what would be the force between them? |
| | A) | 9.0 kN repulsion |
| | B) | 9.0 x 109 N repulsion |
| | C) | 1.0 x 10-6 N repulsion |
| | D) | 9.0 x 1015 N repulsion |
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| 3 | |
What is the force of repulsion between two argon nuclei that are separated by 1.0 nm (10-9m)? The charge on an argon nucleus is +18e. |
| | A) | 2.9 x 1030 N |
| | B) | 2.6 x 1010 N |
| | C) | 75 nN |
| | D) | 7.5 x 10-17 N |
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| 4 | |
Three point charges are placed at the following points on the x-axis: +2.0µC at x=0, -3.0µC at x=40cm, -5.0µC at x=120 cm. Find the force (a) on the -3.0µC charge, (b) on the -5.0µC charge. |
| | A) | (a) -0.55 N, (b) 0.15 N |
| | B) | (a) -0.12 N, (b) 0.27 N |
| | C) | (a) -5.5 x 1011 N (b) 1.5 x 1011 N |
| | D) | (a) -.0055 N, (b) 0.0015 N |
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| 5 | |
Four equal point charges of +3.0µC are placed at the four corners of a square that is 40 cm on a side. Find the force on any one of the charges. |
| | A) | 0.97 N outward along the diagonal |
| | B) | 1.27 N outward along the diagonal |
| | C) | 1.22 N outward along the diagonal |
| | D) | 97 µN outward along the diagonal |
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| 6 | |
One charge of (+5.0µC) is placed at exactly x=0, and a second charge (+7.0µC) at x=100 cm. Where can a third be placed so as to experience zero net force due to the other two? |
| | A) | at x = -5.5 m |
| | B) | at x = 42 cm |
| | C) | at x = 0.35 cm |
| | D) | at x = 46 cm |
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| 7 | |
A charge of +6.0µC experiences a force of 2.0 mN in the +x-direction at a certain point in space. (a) What was the electric field there before the charge was placed there? (b) Describe the force a - 2.0µC charge would experience if it were used in place of the +6.0µC charge. |
| | A) | (a) 1.2 x 10-8 N•C in +x-direction (b) 660 N in -x-direction |
| | B) | (a) 3.0 mC/N in +x-direction (b) 0.165 GN in -x-direction |
| | C) | (a) 0.33 kN/C in +x-direction (b) 0.67 mN in -x-direction |
| | D) | (a) 0.33 N/C in +x-direction (b) 0.66 x 10-6 N in -x-direction |
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| 8 | |
A point charge of -3.0 x 10-5C is placed at the origin of coordinates. Find the electric field at the point x=5.0 m on the x-axis. |
| | A) | 11 kN/C in -x-direction |
| | B) | 1.1 GN/C in -x-direction |
| | C) | 55 kN/C in -x-direction |
| | D) | 1.2 x 10-6 N/C in -x-direction |
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| 9 | |
A tiny, 0.60-g ball carries a charge of magnitude 8.0 µC. It is suspended by a thread in a downward 300 N/C electric field. What is the tension in the thread if the charge on the ball is (a) positive (b) negative? |
| | A) | (a) 5.9 N (b) 8.3 mN |
| | B) | (a) 2.4 kN (b) 5.9 N |
| | C) | (a) 8.3 mN (b) 3.5 mN |
| | D) | (a) 3.5 mN (b) 2.4 kN |
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| 10 | |
Four equal-magnitude (4.0µC) charges are placed at the four corners of a square that is 20 cm on each side. Find the electric field at the center of the square (a) if the charges are all positive, (b) if the charges alternate in sign around the perimeter of the square, (c) if the charges have the following sequence around the square: plus, plus, minus, minus. |
| | A) | (a) zero (b) zero (c) 5.1 MN/C toward the negative side |
| | B) | (a) zero (b) zero (c) 7.2 MN/C toward the negative side |
| | C) | (a) zero (b) zero (c) 5.1 GN/C toward the negative side |
| | D) | (a) zero (b) zero (c) 2.55 MN/C toward the negative side |
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