2 identical copper sphere are separated by 1m in vaccum,how many electrons would have to be removed from 1 sphere and added to other so that they now attract each other with a force of 0.9N

Asked by abhishek | 8th Jun, 2013, 03:13: PM

Expert Answer:

Since the electrons will be traveling from one sphere to another, so if the charge acquired by one sphere would be +q, the other would be -q.
Hence F = kq1q2/r^2
0.9 = |9*10^9 (q)(-q)|/(1)^2
0.9 = 9*10^9 q^2
q^2 = 10^-10
q = 10^-5 
Hence, the electrons transferred = q/e = 10^-5 /1.6E-19 = 6.25*10^13

Answered by  | 9th Jun, 2013, 06:59: AM

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