Physics Electricity

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[匿名]

2012-04-29 3:44 am

29. Two negatively charges A and B are located 1 m apart as shown in the following diagram. Distance between A and B, A and D, B and D and B and E are all 1 m.Charge A carries -1 x 10-6 C and charge B carries -2 x 10-6 C. (a) What is energy required to move a charge of -1 x 10-6 C from point D to point E? 8%(b) What the difference in electric potential between point D and point E? 2%

I don't know how to calculate this question, please help.
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更新1:

Charge A carries -1 x 10^-6 C and charge B carries -2 x 10^-6 C. (a) What is energy required to move a charge of -1 x 10^-6 C from point D to point E? 8%

更新2:

To: 翻雷滾天風卷殘雲 Yes

回答 (2)

天同

2012-04-30 10:30 pm

✔ 最佳答案

Consider point D.
Potential due to charge at A = k(-10^-6)/1 v = -(10^-6)k v
where k is the electrostatic constant (= 9x10^9 N.m^2/C^2)
Potential due to charge at B = k(-2x10^-6)/1 v = -(2x10^-6)k v
Hence, potential at D = [-(10^-6)k - (2x10^-6)k] v = -27,000 v

AE = square-root[1^2+1^2] m = 1.414 m
Hence, potential at point E = [k(-10^-6)/1.414 + k(-2x10^-6)/1] v = -24,365 v

(a) Energy required = [-24365 - (-27000)] x (-1x10^-6) J = -2.64x10^-3 J

(b) Potential difference between D and E = [-27000 - (-24365)] v = -2635 v
(point D is at potential lower than point E)

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用戶25975

2012-04-29 5:17 am

Are AB and AE perpendicular to each other?

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