Answer to Question #257791 in Electricity and Magnetism for brian

Question

1.Three point charges of +16uC are placed at corners of an equilateral triangle of sides of length 2 cm. Calculate potential energy of the system measured with respect to zero when the charges are at infinite distance apart. 2.Two point charges of +20uC are placed 2cm apart. Calculate electric potential and electric field at mid-point of the line joining two charges

Answer 1

1)

$\varphi=3\frac {kq}r=21.6~MV,$

2)

$\varphi=2\frac {kq}{\frac r2}=\frac{4kq}r=36~MV,$

$E=E_1-E_2=\frac{kq}{(\frac r2)^2}-\frac{kq}{(\frac r2)^2}=0.$