QuickCheck 26.1 This is a graph of the x-component of the electric field along the x-axis. The potential is zero at the origin. What is the potential at x = 1m? 2000 V 1000 V 0 V –1000 V –2000 V 2

QuickCheck 26.1 This is a graph of the x-component of the electric field along the x-axis. The potential is zero at the origin. What is the potential at x = 1m? 2000 V 1000 V 0 V –1000 V –2000 V ΔV = –area under curve 3 3

QuickCheck 26.2 At which point is the electric field stronger? At xA At xB The field is the same strength at both. There’s not enough information to tell. 4

QuickCheck 26.2 At which point is the electric field stronger? At xA At xB The field is the same strength at both. There’s not enough information to tell. |E| = slope of potential graph 5

QuickCheck 26.3 An electron is released from rest at x = 2 m in the potential shown. What does the electron do right after being released? Stay at x = 2 m Move to the right (+ x) at steady speed. Move to the right with increasing speed. Move to the left (– x) at steady speed. Move to the left with increasing speed. 6

QuickCheck 26.3 An electron is released from rest at x = 2 m in the potential shown. What does the electron do right after being released? Stay at x = 2 m Move to the right (+ x) at steady speed. Move to the right with increasing speed. Move to the left (–x) at steady speed. Move to the left with increasing speed. Slope of V negative => Ex is positive (field to the right). Electron is negative => force to the left. Force to the left => acceleration to the left. 7

QuickCheck 26.4 Which set of equipotential surfaces matches this electric field? 8

QuickCheck 26.4 Which set of equipotential surfaces matches this electric field? 9

QuickCheck 26.5 The electric field at the dot is 10î V/m –10î V/m

QuickCheck 26.5 The electric field at the dot is 10î V/m –10î V/m 20 V over 2 m, pointing toward lower potential 11

QuickCheck 26.6 A particle follows the trajectory shown from initial position i to final position f. The potential difference ΔV is 100 V 50 V 0 V –50 V –100 V 12

QuickCheck 26.6 A particle follows the trajectory shown from initial position i to final position f. The potential difference ΔV is 100 V 50 V 0 V –50 V –100 V ΔV = Vfinal – Vinitial, independent of the path 13

QuickCheck 26.7 Metal wires are attached to the terminals of a 3 V battery. What is the potential difference between points 1 and 2? 6 V 3 V 0 V Undefined. Not enough information to tell. 14

QuickCheck 26.7 Every point on this conductor is at the same potential as the negative terminal of the battery. Every point on this conductor is at the same potential as the positive terminal of the battery. Metal wires are attached to the terminals of a 3 V battery. What is the potential difference between points 1 and 2? 6 V 3 V 0 V Undefined. Not enough information to tell. 15

QuickCheck 26.8 Metal spheres 1 and 2 are connected by a metal wire. What quantities do spheres 1 and 2 have in common? Same potential Same electric field Same charge Both A and B Both A and C 16

QuickCheck 26.8 Metal spheres 1 and 2 are connected by a metal wire. What quantities do spheres 1 and 2 have in common? Same potential Same electric field Same charge Both A and B Both A and C 17

QuickCheck 26.9 The charge escalator in a battery does 4.8 ×10–19 J of work for each positive ion that it moves from the negative to the positive terminal. What is the battery’s emf? 9 V 4.8 V 3 V 4.8 ×10–19 V I have no idea. 18

QuickCheck 26.9 The charge escalator in a battery does 4.8 ×10–19 J of work for each positive ion that it moves from the negative to the positive terminal. What is the battery’s emf? 9 V 4.8 V 3 V 4.8 ×10–19 V I have no idea. . 19

QuickCheck 26.10 What is the capacitance of these two electrodes? 8 nF Some other value 20

QuickCheck 26.10 What is the capacitance of these two electrodes? 8 nF Some other value 21

QuickCheck 26.11 The equivalent capacitance is 9 μF 6 μF 3 μF 2 μF 22

QuickCheck 26.11 The equivalent capacitance is 9 μF 6 μF 3 μF 2 μF Parallel => add 23

QuickCheck 26.12 The equivalent capacitance is 9 μF 6 μF 3 μF 2 μF 24

QuickCheck 26.12 The equivalent capacitance is 9 μF 6 μF 3 μF 2 μF Series => inverse of sum of inverses 25

QuickCheck 26.13 A capacitor charged to 1.5 V stores 2.0 mJ of energy. If the capacitor is charged to 3.0 V, it will store 1.0 mJ 2.0 mJ 4.0 mJ 6.0 mJ 8.0 mJ 26

QuickCheck 26.13 A capacitor charged to 1.5 V stores 2.0 mJ of energy. If the capacitor is charged to 3.0 V, it will store 1.0 mJ 2.0 mJ 4.0 mJ 6.0 mJ 8.0 mJ 27