Respostas

2014-05-31T12:16:52-03:00
V = k .Q / d

k ~> 9.10⁹

20 cm = 0,2 m

 -10 nC = - 10 .10⁻⁹ C


U = 9.10⁹ . | - 10 .10⁻⁹ | / 0,2 = 450 Volt