Answer to Question #99899 in Mechanics | Relativity for Fahad

Question

A dipole is consisting of an electron and proton, 4e-10 m apart. compute the electric field at a distance of 2e-8 m on a line making perpendicular with the dipole exist from the centre of the dipole?
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Answer 1

For the situation shown above, we can first calculate the distance from the charges to the considered point:

$$d=\sqrt{(4\cdot10^{-10})^2+(2\cdot10^{-8})^2}=2\cdot10^{-8}\text{ m}.$$

Now calculate the magnitude of the vectors of the electric field lines at the considered point:

$$E=E_-=E_+=ke/d^2.$$

However, the field has two components: vertical and horizontal. The horizontal component of the total resultant field is

$$E_x=E_+\text{ cos}\alpha+E_-\text{ cos}\alpha=2E\text{ cos}\alpha=\\ =179751036\text{ V/m}.$$

The vertical component of the resultant field is

$$E_y=E_+\text{ sin}\alpha-E_-\text{ sin}\alpha=0.$$