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Question
Two charges 5 μC and -4μC are kept 5.0 m apart at points A and B respectively. How much work will have to be done to move the charge at A through a distance of 5.0 m further away from point B along the line BA?
Solution
Given: q1 = 5 µC = 5 × 10−6 C, q2 = 4 μC = −4 × 10−6 C, r1 = 5 m
To find: Work done (W)
∴ V = `1/(4πε_0)"q"_1/"r"`
= 9 × 109 × `(5xx10^-6)/5`
∴ V = 9 × 103 V
∴ V = `"W"/"q"_1`
∴ W = V × q1
W = 9 × 103 × 5 × 10-6
W = 45 × 10-3
W = 4.5 × 10-2 J
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