1 / 27

Electric Field Contents: Basic Concept Calculating electric Field example Whiteboards

Electric Field Contents: Basic Concept Calculating electric Field example Whiteboards Point Charges Examples Whiteboards Electric Fields in Charge Arrays. Gravitational Field. Electrical Field. Force on mass Force on charge g = Field strength E = Field strength

beate
Download Presentation

Electric Field Contents: Basic Concept Calculating electric Field example Whiteboards

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electric Field • Contents: • Basic Concept • Calculating electric Field example • Whiteboards • Point Charges • Examples • Whiteboards • Electric Fields in Charge Arrays

  2. Gravitational Field Electrical Field • Force on mass Force on charge • g = Field strength E = Field strength • g = 9.81 N/kg (on earth) E is in N/C • F = mg F = qE (E = F/q) • Direction: Uh… down Direction: F on + Charge • Force: Force: • F = Gm1m2 F = kq1q2 • r2 r2 • Field: Field: • g = F = Gm E = F = kq • m r2q r2 • G = 6.67x10-11 Nm2kg-2 k = 8.99x109 Nm2C-2 TOC

  3. Electric Field Direction: Force This Way +q E Force This Way -q Example 1 - A +125 C charge experiences a force to the right of .0175 N. What is the Electric field, and its direction? E = F/q = .0175 N/125x10-6 C = 140 N/C to the right TOC

  4. Which way is the electric field? (wwpcd?) + + + + + - - - - -

  5. Which way is the electric field? - - - - - + + + + +

  6. Which way is the electric field? +

  7. Which way is the electric field? + -

  8. Electric Field Example 2 - An electron travels through a region where there is a downward electric field of 325 N/C. What force in what direction acts on the electron, and what is its acceleration? F = Eq = (325 N/C down)(-1.602x10-19C) = -5.21x10-17N down F = ma, a = F/m = (5.21x10-17 N)/(9.11x10-31kg) = 5.72x1013 m/s/s TOC

  9. Whiteboards: Uniform field 1 | 2 | 3 | 4 TOC

  10. Ishunta Dunnit notices that a charge of -125 C experiences a force of .15 N to the right. What is the electric field and its direction? E = F/q = (.15 N)/(-125x10-6 N) = -1200 N/C right or 1200 N/C left W 1200 N/C left

  11. Doan Botherme places a +12 mC charge into an upward 160 N/C electric field. What force in what direction does it experience? E = F/q, q = 12x10-3 C, E = 160 N/C up F = 1.92 = 1.9 N up W 1.9 N up

  12. Alfred O. Dadark is on a planet where a mass of 0.12 kg experiences a downward force of 7.80 N. What is the gravitational field on the surface of this planet? g = F/m, m = 1.12 kg, E = 7.80 N down g = (7.80 N down)/(0.12 kg) = 65 N/kg down W 65 N/kg down

  13. Telly Vishun places an unknown charge into a known upward electric field of 612 N/C, and the charge experiences a downward force of .851 N. What is the charge? E = F/q, E = 612 N/C up, F = .851 N down q = -.0013905 C = -1.39 mC W -1.39 mC

  14. Sal F. Hone levitates a .00125 kg ball with an upward electric field of 590 N/C. What is the charge on the ball? (Hint gravity = electrical force) Eq = mg E = F/q, F = Eq, F = mg, m = .00125 kg, g = 9.80 N/kg, E = 590 N/C q = 2.07627E-05 = +20.8 C W +20.8 C

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

  16. Fields around points of mass or charge Example: What is the electric field 2.0 m to the right of a -21 μC charge? E = kq/r2 = (8.99E9)(-21E-6)/(22) = -47,197.5 N/C (away) or 47,000 N/C toward a, b, c are points, Q is a charge TOC

  17. Whiteboards: Field relative to points 1 | 2 | 3 TOC

  18. 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) W 71.5 N/C to the left

  19. 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 W +.11 C

  20. 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) W 1.1 x 107 m

  21. 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 W 12 m

  22. 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) W 6.54E6 N/C to the left

  23. A B Each grid is a meter. If charge A is -14.7 μC, and charge B is +17.2 μC, calculate the electric field at the origin: y x

  24. mag angle x y A 7773.7 165.96 -7541.6 1885.4 B 19328.5 45 13667.3 13667.3 6125.7 15552.7 Mag 16,715 N/C angle 68.5º (trig angle)

  25. Q2 Q1 Electric Fields in Non Linear Arrays Find the electric Field at point A: A +3.1 C +1.5 C 75 cm 190 cm • Calculate the individual E-Fields • Figure out direction (angle) • Add E-Fields (as vectors) TOC

  26. Q2 Q1 Electric Fields in Non Linear Arrays E1 E2 A • Calculate the individual E-Fields • Figure out direction (angle) • Add E-Fields (as vectors) +3.1 C +1.5 C 75 cm 190 cm • E1 = kq1 = k(1.5C) = 11,987 N/C • r2 (.752 + .752) • E2 = kq2 = k(3.1C) = 6,679.2 N/C • r2 (1.92 + .752) TOC

  27. Q2 Q1 Electric Fields in Non Linear Arrays E1= 11,987 N/C E2= 6,679.2 N/C A 1 2 +3.1 C +1.5 C 75 cm 190 cm • Figuring out direction: • 1 = 45o • 2 = Tan-1(.75/1.9) = 21.54o • T = 180-21.54 = 158.46o Really hoping I don’t need to show any more… TOC

More Related