What charge is required to suspend a 1.7*10^-13kg oil drop in an electric field of 2.5*10^5 N/C?
Draw the Free Body Diagram
Apply [tex] \Sigma F[/tex] = [tex] \vec F_m_a_g + \vec F_w_t [/tex] = 0
As in case of equilibrium
Also apply the charge quantization
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