Chapter 23Electric Fields

Chapter 23—Electric Fields

MULTIPLE CHOICE

• Each of two small non-conducting spheres is charged positively, the combined charge being 40

C. When the two spheres are 50 cm apart, each sphere is repelled from the other by a force of magnitude 2.0 N. Determine the magnitude of the smaller of the two charges.a.1.4 C b.1.1 C c.2.0 C d.3.3 C e.17 C ANS:A PTS:3 DIF:Challenging

• A particle (charge = +40 C) is located on the x axis at the point x = 20 cm, and a second

particle (charge = 50 C) is placed on the x axis at x = +30 cm. What is the magnitude of the total electrostatic force on a third particle (charge = 4.0 C) placed at the origin (x = 0)?a.41 N b.16 N c.56 N d.35 N e.72 N ANS:C PTS:2 DIF:Average

• In the figure, if Q = 30 C, q = 5.0 C, and d = 30 cm, what is the magnitude of the

electrostatic force on q?a.15 N b.23 N c.zero d.7.5 N e.38 N ANS:D PTS:2 DIF:Average

• A charge of +80 C is placed on the x axis at x = 0. A second charge of 50 C is placed on

the x axis at x = 50 cm. What is the magnitude of the electrostatic force on a third charge of 4.0 C placed on the x axis at x = 30 cm?a.13 N b.77 N c.39 N d.25 N e.45 N ANS:B PTS:2 DIF:Average 1 / 4

• Three point charges are positioned on the x axis. If the charges and corresponding positions are

+32 C at x = 0, +20 C at x = 40 cm, and 60 C at x = 60 cm, what is the magnitude of the electrostatic force on the +32-C charge?a.84 N b.12 N c.36 N d.50 N e.48 N ANS:B PTS:2 DIF:Average

• A particle (m = 50 g, q = 5.0 C) is released from rest when it is 50 cm from a second particle

(Q = 20 C). Determine the magnitude of the initial acceleration of the 50-g particle.a.54 m/s 2 b.90 m/s 2 c.72 m/s 2 d.65 m/s 2 e.36 m/s 2 ANS:C PTS:2 DIF:Average

• A point charge Q is placed on the x axis at x = 2.0 m. A second point charge, Q, is placed at x

= 3.0 m. If Q = 40 C, what is the magnitude of the electrostatic force on a 30-C charge placed at the origin?a.7.2 N b.3.9 N c.1.5 N d.14 N e.8.1 N ANS:C PTS:2 DIF:Average

• A point charge Q is placed on the x axis at x = 2.0 m. A second point charge, Q, is placed at

x = 1.0 m. If Q = 60 C, what is the magnitude of the electrostatic force on a 40-C charge placed at the origin?a.16 N b.27 N c.32 N d.11 N e.3.0 N ANS:B PTS:2 DIF:Average

• A point charge Q is placed on the x axis at the origin. An identical point charge is placed on the

x axis at x = 1.0 m and another at x = +1.0 m. If Q = 40 C, what is the magnitude of the electrostatic force on the charge at x = +1.0 m?a.29 N b.14 N c.11 N d.18 N e.7.0 N ANS:D PTS:2 DIF:Average 2 / 4

10.If a = 3.0 mm, b = 4.0 mm, Q1 = 60 nC, Q2 = 80 nC, and q = 36 nC in the figure, what is the magnitude of the electric force on q?a.5.0 N b.4.4 N c.3.8 N d.5.7 N e.0.60 N ANS:C PTS:2 DIF:Average 11.If a = 3.0 mm, b = 4.0 mm, Q1 = 60 nC, Q2 = 80 nC, and q = 30 nC in the figure, what is the magnitude of the electric force on q?a.1.4 N b.1.0 N c.1.7 N d.2.0 N e.0.50 N ANS:B PTS:2 DIF:Average 12.If a = 3.0 mm, b = 4.0 mm, Q1 = 60 nC, Q2 = 80 nC, and q = 24 nC in the figure, what is the magnitude of the electric force on q?a.2.7 N b.1.9 N c.2.3 N d.1.5 N e.0.52 N ANS:D PTS:2 DIF:Average 13.If a = 3.0 mm, b = 4.0 mm, Q1 = 60 nC, Q2 = 80 nC, and q = 32 nC in the figure, what is the magnitude of the electric force on q? 3 / 4

a.1.6 N b.1.3 N c.1.9 N d.2.2 N e.0.040 N ANS:B PTS:2 DIF:Average 14.Three point charges, two positive and one negative, each having a magnitude of 20 C are placed at the vertices of an equilateral triangle (30 cm on a side). What is the magnitude of the electrostatic force on the negative charge?a.80 N b.40 N c.69 N d.57 N e.75 N ANS:C PTS:2 DIF:Average 15.Three point charges, two positive and one negative, each having a magnitude of 20 C are placed at the vertices of an equilateral triangle (30 cm on a side). What is the magnitude of the electrostatic force on one of the positive charges?a.69 N b.40 N c.80 N d.57 N e.20 N ANS:B PTS:2 DIF:Average 16.A point charge Q is placed at the origin. A second charge, 2Q, is placed on the x axis at x = 3.0 m. If Q = 50 C, what is the magnitude of the electrostatic force on a third point charge, Q, placed on the y axis at y = +4.0 m?a.2.5 N b.3.0 N c.3.7 N d.4.4 N e.1.8 N ANS:B PTS:3 DIF:Challenging 17.Three identical point charges Q are placed at the vertices of an equilateral triangle (length of each side = 2.0 m). If Q = 60 C, what is the magnitude of the electrostatic force on any one of the charges?

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