Calculating the Electric potential of charges

Question

Three charges are at the vertices of an isosceles triangle. With q = 7.00 nC, the two charges at the base of the triangle are separated by 2.00 cm and each has a charge of -q. The charge q at the top of the triangle is 4.00 cm from each of the charges at the base.

How can I calculate the electric potential halfway between the charges on the base of the triangle?

Answer 1

Hi Oranuo,

The fundamental idea here is that the electric potential produced by a collection of charges is equal to the sum of the electric potentials produced by each of those charges, separately. Depending on what notation your teacher/book use, we often write the electric potential produced by a point charge as

V=kQ⁄r,

where k is the electric constant, Q is the electric charge of that point charge, and r is how far you are away from it. The hardest part for your problem is to figure out what all those values of r are equal to. I'd suggest drawing the picture and, by using a little big of trigonometry, you should be able to figure out what they are. Then you'll add up the potentials like this

kQ_1/r_1 + kQ_2/r_2 + kQ_3/r_3.

Good luck!