2. A region of space contains a uniform electric field, directed toward the right, as shown in the figure. Which statement about this situation is correct? A. The potential at all three locations is the same. 2. B. The potentials at points A and B are equal, and the potential at point C is higher than the potential at point A. C. The potential at points A and B are equal, and the potential at point C is lower than the potential at point A. •A D. The potential at point A is the highest, the potential at point B is the second highest, and the potential at point C is the lowest. •C B E

(a) What is the potential between two points situated 10 cm and 20 cm from a 3.0 C point charge? (b) To what location should the point at 20 cm be moved to increase this potential difference by a factor of two?

(a) What is the capacitance of a parallel plate capacitor having plates of area 1.50 m2 that are separated by 0.0200 mm of neoprene rubber? (b) What charge does it hold when 9.00 V is applied to it?

(a) A certain parallel-plate capacitor has plates of area 4.00 m2 , separated by 0.0100 mm of nylon, and stores 0.170 C of charge. What is the applied voltage? (b) What is unreasonable about this result? (c) Which assumptions are responsible or inconsistent?

The potential in a region between x = 0 and x = 6.00 m V = a + bx, where a = 10.0 V and b = -7.00 V/m. Determine (a) the potential at x = 0, 3.00 m, and 6.00 m and (b) the magnitude and direction of the electric field at x = 0, 3.00 m. and 6.00 m.

Review. In fair weather, the electric field in the air at a particular location immediately above the Earth's surface is 120 N/C directed downward, (a) What is the surface charge density on the ground? Is it positive or negative? (b) Imagine the surface charge density is uniform over the planet. What then is the charge of the whole surface of the Earth? (c) What is the Earths electric potential due to this charge? (d) What is the difference in potential between the head and the feet of a person 1.75 m tall? (Ignore any charges in the atmosphere.) (e) Imagine the Moon, with 27.3% of the radius of the Earth, had a charge 27.3% as large, with the same sign. Find the electric force the Earth would then exert on the Moon, (f) State how the answer to part (e) compares with the gravitational force the Earth exerts on the Moon.

(a) Plot the potential of a uniformly charged 1-m rod with 1 C/m charge as a function of the perpendicular distance from the center. Draw your graph from s = 0,1 in to s = 1.0m. (b) On the same graph, plot the potential of a point charge with a 1-C charge at the origin, (c) Which potential is stronger near the rod? (d) What happens to the difference as the distance increases? Interpret your result.

True or False? (a) From the definition of capacitance C = Q/V it follows that an uncharged capacitor has a capacitance of zero. (b) As described by the definition of capacitance, the potential difference across an uncharged capacitor is zero.

A long thin wire is used in laser printers to charge the photoreceptor before exposure to light. This is done by applying a large potential difference between the wire and the photoreceptor. a. Use Equation 26.23, V(r)=20lnRr to determine a relationship between the electric potential V and the magnitude of the electric field E at a distance r from the center of the wire of radius R (r R). b. Determine the electric potential at a distance of 2.0 mm from the surface of a wire of radius R = 0.80 mm that will produce an electric field of 1.8 106 V/m at that point.

A capacitor is made from two flat parallel plates placed 0.40 mm apart. When a charge of 0.020C is placed oil the plates the potential difference between them is 250 V. (a) What is the capacitance of the plates? (b) What is the area of each plate? (c) What is the charge on the plates when the potential difference between them is 500 V? (d) What maximum potential difference can be applied between the plates so that the magnitude of electrical fields between the plates does not exceed 3.0 MV/m?