Find the electric field intensity of transformer oil (εr = 2 approx) with density 1/4π (in 109 units)

The electric field intensity (E) in a medium, such as transformer oil, with a relative permittivity (εr) is not directly determined by the relative permittivity or the density alone. Instead, the electric field in a region is determined by the presence of electric charges and the distribution of these charges in and around that medium.

However, to provide context to your query, we could interpret it as seeking the electric field (E) in a scenario where a certain electric potential or voltage is applied across a medium, like transformer oil, assuming no free charges are present within the oil itself. In a vacuum or free space, the electric field (E) due to a point charge is given by Coulomb’s law, (E = frac{k cdot q}{r^2}), where (k) is Coulomb’s constant ((8.987 times 10^9 N m^2/C^2)), (q) is the charge in Coulombs, and (r) is the distance from the charge in meters.

In a medium like transformer oil, this field is modified by the material’s relative permittivity ((ε_r)), which is a measure of how an electric field within the material is reduced compared to the field in a vacuum. The electric field in a material is thus given more generally by (E = frac{k cdot q}{ε_0 cdot ε_r cdot r^2}), where