A negative point charge q1 = 25 nC is located on the y axis at y = 0 and a positive point charge q2 = 10 nC is located at y =14 cm. Find the y coordinate of the points where the net electric potential due to these two charges is zero.

 y = 0.1 m

Explanation:

The electrical power for point loads is

         V = k Sum qi / ri

in this case

         V = k ()

indicate that V = 0

        r₂ =

the distance r1 is

         r₁ = y -0

the distance r2

         r₂ = 0.14 -y

we substitute

        0.14 - y =  y

          y ( ) = 0.14

          y 1.4 = 0.14

          y = 0.14 / 1.4

          y = 0.1 m

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

wavelength divides in half and speed stays the same.