The sphere on the right has a charge of +2q. The sphere to the left has a charge of – 3q.

1. The sphere on the right has a charge of +2q. The sphere to the left has a charge of – 3q. Which of the following pictorial descriptions of the electric field best matches the above verbal description? Construct a pictorial description of the electric field lines that best matches the above verbal description. 2 1 4 3

2. Jenny, a student in an introductory physics class sees the following equation: (1.6 x 10-5 C) (5.0 x 106 N/C) – 10 N = (.015 kg) a Which of the following verbal descriptions best matches the above mathematical representation? Write a verbal description that best matches the above mathematical representation. • A proton is in electric field that experiences a 10 N force holding it back. • A mass of 0.015 kg is experiencing just one force due to an electric field of 5.0 x 106 N/C. • A charged particle is being accelerated through an electric field but also experiences some force in the opposite direction. • A particle has a charge of 1.6 x 10-5 C is being accelerated only by the result of a 10 N force applied to it.

3. +q x x x +q +q +q +q x Two equal magnitude charged spheres are held near each other. The electric field measured at point A points at a 45o angle North of West. Which of the following pictures below matches the above description? Construct a picture which could match the above description. 3 1 A A A 2 x +√2q x

4. Vinit = 100 V Vfinal = 0 V A proton starts at rest between metal sheets with a potential difference of 100 Volts across them. Which of the following motion diagrams could match the motion of the proton? Construct a motion diagram that matches the proton’s motion when released. 1 2 3 4

5. Sara is looking over her physics textbook and sees a situation described mathematically below. The same situation is described in words below. Decide which description fits the mathematical description best. Describe the same situation in words below. • 3 x 1012 protons travel through a wire each hour. • 3 x 1012 electrons travel through a wire in each hour. • 3 x 1012 electrons travel through a wire in just under an hour. • 3 x 1012 Coulombs of charge travel through a wire in just under an hour.

6. A picture is drawn below showing equipotential surfaces for two fixed charged pith balls. Which of the following verbal descriptions best match the above equipotential surfaces? Write a verbal description that matches the above equipotential surfaces. • Both pith balls are positively charged. • Both pith balls are negatively charged. • One pith ball is positively charged, the other is negatively charged. • Both 1 and 2 are possible solutions

7. A situation is described with an energy bar chart below. KoPEgoPEsoPEqoWKPEgPEsPEq DEint 0 Which of the following verbal representations best matches the above bar chart? Write a verbal representation to best match the above bar chart. • A charged object shoots straight up away from another charged object and reaches its highest point. • A charged object is high above the ground in an electric field. The field pulls the charged particle downward. We see the system’s energy when it is halfway down to the ground.. • A charged object initially at rest moves at an angle away from a second like charged object. At the top of the projectile path the object is moving horizontally. • A proton is held below a negatively charged sphere and released.

8. -q3 +q2 +q1 y y y y x x x x Three identical magnitude charged spheres are shown below. Which electrical force diagram corresponds to the pictorial representation? Construct an electrical force diagram to correspond to the pictorial representation for q3. 3 1 4 2

9. A student sees in a textbook the picture below of two charged spheres and the corresponding electric field lines. Which of the following verbal descriptions best matches the above pictorial representation? Construct a verbal description that best matches the above pictorial representation. • 1 The two spheres have charges that are opposite but equal in magnitude. • 2 The left sphere has a positive charge that is twice the magnitude of the negative charge on the right. • The left sphere has a negative charge that is twice the magnitude of the positive charge on the right. • 4 The right sphere must not have all of the lines drawn into it.

10. y y y y y y y y x x x x A positively charged sphere is held in a fixed position relative to a negatively charged sphere on the left with half the magnitude of electric charge. Which pair of electric force diagrams below best matches the above verbal description? Construct a pair of electric force diagrams that best matches the above verbal description. 1 3 2 4

11. Four charged spheres, not necessarily the same magnitude charge, are placed at the corners of a square. The net electrical force on sphere C is zero. C A D B What are the signs of the charged spheres to match the above verbal description? What are the signs of the charged spheres to match the above verbal description? A B C D 1 + – – + 2 – – – + 3 – – + + 4 + + + + 5 + – + –

12. Final Initial + + + + A process is shown in the picture below. The charged sphere on the right is fixed. The left charged sphere is on a moveable cart. It is initially held by a wedge, then let go. What energy bar chart best matches the pictorial representation? Construct an energy bar chart that best matches the pictorial representation. KoPEgoPEsoPEqoWKPEgPEsPEq DEint 1 2 3

13. A real situation is described mathematically: ½ m vo2 + q Vo = ½ m v2 + q V ½ (.001 kg)(0 m/s)2 + (1.0 x 10-6 C)(12 V) = ½ (.001 kg) v2 + (1.0 x 10-6 C)(0 V) The same situation is described verbally below. Which description fits the above mathematical description best? Construct a verbal description that fits the above mathematical description best. 1 A .001 kg object is moving across the plates of a capacitor at a constant speed. 2 An object whose charge is 1.0 x 10-6 C is initially moving at some speed, v away from a 12 Volt plate until it comes to rest. 3 A .001 kilogram object that has a charge is initially at rest in a capacitor but then moves across the 12 Volt potential difference. 4 The plate where the object comes to has no charge on it.