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Electric fields around point charges

Electric fields around point charges. Away from positive. Toward negative. Direction of E field is:. Fields around points of mass or charge. a, b, c are points, Q is a charge. Example: What is the electric field 2.0 m to the right of a -21 μ C charge?. 47,000 N/C left. A. C.

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Electric fields around point charges

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  1. Electric fields around point charges Away from positive Toward negative Direction of E field is:

  2. Fields around points of mass or charge a, b, c are points, Q is a charge

  3. Example: What is the electric field 2.0 m to the right of a -21 μC charge? 47,000 N/C left

  4. A C +12.5 C -187 C x 72.1 cm 11.2 cm What is the electric field at the x? (Magnitude and direction) • EA = kqA = 8.958E6 N/C to the left (away from +) • r2 • EC = kqC = 2.423E6 N/C to the right (toward -) • r2 • = - 8.958E6 N/C + 2.423E6 N/C = -6.54E6 N/C (Left) 6.54E6 N/C to the left

  5. Whiteboards: Field relative to points 1 | 2 | 3

  6. Vera Similitude measures the electric field 13.5 m to the right of a -1.45 C charge. What electric field in what direction? • E for a point charge: • E = kq • r2 • k = 8.99x109 Nm2C-2, q = -1.45x10-6 C, r = 13.5 m • E = -71.5 N/C away from the charge, or to the left (toward the negative charge) 71.5 N/C to the left

  7. Vesta Buhl measures an electric field of 2,120 N/C, 67 cm from a charge of unknown value. The electric field is away from the charge. What is the charge? • E for a point charge: • E = kq • r2 • k = 8.99x109 Nm2C-2, E = 2,120 N/C, r = .67 m • q = 1.06x10-7 C = +.11 C. It is a positive charge as the E-field is away from it +0.11 C

  8. Amelia Rate measures a gravitational field of 3.4 N/kg. What distance is she from the center of the earth? (Me = 5.98 x 1024 kg. ) • g for a point mass: • g = Gm • r2 • G = 6.67x10-11 Nm2kg-2, g = 3.4 N/kg, m = 5.98x1024 kg • r = 10831137.03 m = 10.8 x 106 m (re = 6.38 x 106 m) 1.1 x 107 m

  9. Tara Bull measures an electric field of 10. N/C what distance from an electron? • E for a point charge: • E = kq • r2 • k = 8.99x109 Nm2C-2, E = 10 N/C, q = 1.602x10-19 C • r = 1.20008x10-5 m = 12 m 12 m

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