Question

Three charges are arranged in an equilateral triangle with sides of 4 cm. The coordinates and corresponding charge values are as follows: +4q at (-2,0); +2q at (2,0); -q at (0,a). The elementary charge of an electron is given by q = -1.602 x 10^-19 C.

a) Determine the y-coordinate a of the third charge

b) Determine the electric field at the centre of the equilateral triangle

c) Determine the torque that acts on the dipole and the work done to align the dipole depicted in the picture the center of the equilateral triangle with the resulting field at the corner. The dipole exhibits a dipole ...?

Answer 1

To determine the answer of Part A draw the equilateral triangle and the to determine the coordinates of of the third charge use that triangle.
To calculate the gravitational field strength in part B from each of the charges use the following equation.

E=kcq/r2

If you would add those values then you can use the symmetry about the y axis to make the vector addition a litter easier.